HGPPI Applikationsbeispiele V9 En

HGPPI Servopneumatic Parallel Gripper Application Examples

Festo HGPPI 2

The application examples are for familiarising oneself with the functions of the HGPPI. This description gives instructions on command control of the HGPPI. Installation, startup and diagnosis of the HGPPI are described in the manual 543299. It is absolutely necessary to observe the safety instructions as well as the intended use of the module. Please also observe the safety instructions in the manuals for the pneumatic components used. The HGPPI and the connectable modules and cables may only be used as follows: as intended only for industrial applications without any modifications by the user.

Permitted are conversions or alterations as described in the documentation enclosed with the product.

in technically perfect condition.

Comply with national and local laws and technical regulations.

Target group This description is intended exclusively for technicians trained in control and auto-mation technology, who have experience in installing, commissioning, programming and diagnosing respective fieldbus stations.

Service Please consult your local Festo Service if you have any technical problems.

Intended use

3 Festo HGPPI

Intended use _________________________________________________________ 2

Contents ____________________________________________________________ 3

1 HGPPI application examples_________________________________________ 5

1.1 Theoretical example - Gripping forces _____________________________ 7

1.2 Theoretical example - Basic parameters __________________________ 10

1.3 Theoretical example - Power failure ______________________________ 12

1.4 Working with the program examples _____________________________ 14

1.4.1 Basic requirements _______________________________________ 14

1.4.2 Preparing the Siemens controllers ___________________________ 14

1.4.3 Master reset of the CPU 314C-2DP___________________________ 14

1.4.4 Loading the program examples _____________________________ 15

1.4.5 Adapting the hardware configuration ________________________ 17

1.4.6 Overview of the modules __________________________________ 18

1.5 Program example 1 - Sequence control ___________________________ 21

1.6 Program example 2 - Read/write parameters ______________________ 27

1.7 Program example 3 - Workpiece detection ________________________ 33

1.8 Program example 4 - Reliable application of forces _________________ 37

1.9 Program example 5 - Travel speed _______________________________ 40

1.10 Program example 6 - Internal gripping__________________________ 44

1.11 Program example 7 - Step sequence ___________________________ 48

Index ______________________________________________________________ 49

Contents

Contents

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5 Festo HGPPI

The application examples for the parallel gripper HGPPI allow you to get started with the variety of functions and applications of the gripper quickly and in a practical way.

Knowledge about the following is required to be able to use the application examples successfully:

Knowledge about the use of Windows 95/98/2000/ME/NT4.0 Basic principles of PLC programming with STEP7 Basic principles of PROFIBUS DP

Required hardware and software

PC, operating system Windows 95/98/2000/ME/NT4.0 with Minimum: 133MHz and 64MB RAM, free disk memory approx. 65 MB Ideal: 500MHz and 128MB RAM, free disk memory approx. 65 MB

Software STEP 7 V 5.2 or higher MPI interface for the PC (e.g. PC adapter) PLC SIMATIC S7-300 with e.g. CPU 313C-2DP

with 8 digital inputs and outputs PROFIBUS cable with 2 PROFIBUS plugs Parallel gripper HGPPI Simulation of 8 inputs and outputs Power supply 24 V DC

1 HGPPI application examples

HGPPI Application Examples

Festo HGPPI 6

Ein-/ Au

sgnge

Profibus-DP

Kommunikation

Verso

rgung

24VDC

Versorgung 24VDC

3

2

1

4

Example - Configuration of the hardware for the application of the program examples

Pos. Designation Source

1 HGPPI parallel gripper Festo AG

2 S7 controller Festo Didactic, EduTrainer S7-313C-2DP

3 Simulation box Festo Didactic, digital simulation box

4 Power supply unit Festo Didactic, tabletop power supply unit

5 Bus cable, PLC HGPPI Festo Didactic, Profibus cable

You will find more information under:

www.festo.com

www.festo-didactic.com


7 Festo HGPPI

HGPPI Servopneumatic parallel gripper

Topic: Gripping forces

Description of problem: Which forces have an effect on the gripper jaws? Which effect does the supply pressure have on the gripping force?

Design and mode of operation of the gripper

There is no mechanical forced coupling of the gripper jaws that is typical for stan-dard gripper jaws here in order to enable the variable positioning of each individual gripper jaw. The result is a pneumatic cylinder system with three pressurised cham-bers and two pistons. The pressurised chamber in the middle has an effect on both pistons (see schematic diagram).

For the position sensing of the two gripper jaws, each piston is equipped with an analogue displacement encoder on the basis of a hall effect sensor. In addition, all three pressurised chambers have their own pressure sensor. The pneumatic signals are used for the position controller as well as for the indirect regulation of the gripping force via the chamber pressures.

Design of the servo-pneumatic parallel gripper HGPPI

The air supply and exhaust for the cylinder chambers are ensured via integrated proportionally controllable piezo valves. Each chamber is equipped with two 2/2W valves that are each wired in the same way as a 3/3W proportional valve.

A position controller with subordinate non-linear pressure regulation is used as the regulation structure. That makes it possible to operate the gripper jaws by the regulation of either the position or the force.

1.1 Theoretical example - Gripping forces


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The force is controlled indirectly via the pressure. The maximum possible gripping forces depend on the supply pressure. The actual gripping force of the gripper jaws is reduced by the static friction of the piston seals in the cylinder system.

aftHaftreibkrsdruckVersorgungGreifkraft

With the HGPPI, the following main functions can be implemented.

A workpiece is held with a defined force by friction locking. With the HGPPI, the gripper fingers can be prepositioned via friction locking or a position or force threshold can be queried.

A workpiece gripped using mechanical locking requires the precise positioning of the gripper fingers. The gripping forces can be monitored to detect collisions.

Friction locking

Mechanical locking


9 Festo HGPPI

With external gripping, the gripper fingers are positioned with the HGPPI even in small spaces. The force is adapted to the workpiece properties.

With internal gripping, the holding force takes effect from the inside to the outside. The HGPPI allows the direction of action to be adapted to the gripping forces and the coordinate system.

F F

When gripped, the workpiece can be positioned securely in the gripper jaw stroke with a positioning accuracy of 0.1 mm.

External gripper

Internal gripper

Positioning


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Topic: Using the basic parameters

Description of problem: How can the closing time be optimised?

Parameters can be set as basic parameters with the system data in the GSD file of the HGPPI PROFIBUS slave (see user description). The system parameters are initialised by the PLC master when the HGPPI slave starts up. Functions 3 and 4 can be used to write or read parameters (also see application example 5, Writing parameters). System parameters can be set to optimise the positioning speed and build up the force:

Max. set force ramp F [N/s], P 1.2 Range 1...600 (default value: 100)

Max. set speed vmax [mm/s], P1.3 Range 1...200 (default value: 100)

Tolerance position [0.01 mm], P 1.0 Range 1...390 (default value: 50)

vmax

F [N/s]

Basic parameters: force ramp and speed

In the case of the optimisation of time-critical processes or cycle times, as much time as possible needs to be saved with each movement.

The basic parameter "force ramp" F affects the build-up and reduction of force for gripping commands with nominal force parameters. When the force ramp is increased, the set gripping force is established quickly. A reduction of the force ramp results in the gentle build-up of force for sensitive gripping applications.

1.2 Theoretical example - Basic parameters


11 Festo HGPPI

When the gripper jaws are positioned or moved, a speed profile is processed. Depending on the positioning or travel distance, the grippers are accelerated to the "maximum set speed" vmax and decelerated before this position is reached. With short strokes, the "maximum set speed" might not be reached. Any change to the "maximum set speed" will not affect the abruptness of the increase and reduction of the speed profile.

vmax

t

Speed profile

If the double-jaw command "Function 33" is used for the movement, a speed factor [%] can be preselected as nominal value parameter. The speed factor applies to a percentage value of the maximum set speed vmax.

When the single-jaw and double-jaw commands are used for positioning, a position tolerance factor [%] can be specified for some commands. The position tolerance factor applies (in percent) to the "tolerance position" in the system parameters set in the GSD file. The "tolerance position" is determined using a unit of 0.01 mm. With a "tolerance position" of '50' (0.5 mm) and a position tolerance factor of '80' (80%), the positioning accuracy has a tolerance of 0.4 mm.


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Topic: Voltage failure

Description of problem: How does the HGPPI react if the load or logic voltage fails?

For the connection to the power supply, the HGPPI has a 4-pin plug.

34

1 2

Power supply

1 Logic voltage

2 Load voltage

3 0V

4 Screen

1.3 Theoretical example - Power failure


13 Festo HGPPI

Reaction of the HGPPI in the event of a load voltage failure

A load voltage failure will result in an error. When the load voltage is restored, the error can be acknowledged using the "Error reset" command. By resetting the error, the desired position is set to the actual position and the gripper is held in the current position in a controlled manner.

Reaction of the HGPPI in the event of a logic voltage failure

In the event of a logic voltage failure, the PROFIBUS DP will fail. In the PROFIBUS DP master system, the "Slave not available" error can be diagnosed. When the logic voltage is restored, the HGPPI reacts in the same way as with a restart.


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Topic: Working with the program examples

Description of problem: How can the program examples be used?

1.4.1 Basic requirements

The enclosed PLC programs are designed for controllers with 8 digital inputs and outputs.

1.4.2 Preparing the Siemens controllers

Controllers: Siemens S7-314C-2DP or similar Programming software: Siemens STEP7 Version 5.2 or higher

1. Connect the PC and the controller to the PC adapter using the RS232

programming cable 2. Switch on the power supply unit 3. Unlock the EMERGENCY STOP pushbutton (if available) 4. Master reset of PLC memory:

Wait until the PLC has completed its check routines.

1.4.3 Master reset of the CPU 314C-2DP

Press the mode selector after MRES. Hold the mode selector in this position until the STOP LED lights up for the second time and remains lit continuously (equivalent to 3 s). Then release the mode selector.

You must press the mode selector again within 3 seconds after MRES. The STOP LED starts flashing quickly and the CPU performs a master reset. Now you can release the mode selector.

When the STOP LED lights up permanently, the CPU has completed the master reset.

The data of the MMC (Micro Memory Card) is not deleted. This can be triggered by setting up a connection to the PLC in the "Target system / Display available stations" menu and deleting all modules in the module folder.

1.4 Working with the program examples


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1.4.4 Loading the program examples

1. Switch the mode selector to the STOP position 2. Start the programming software 3. De-archive the HGPPI_Application.zip file

Note Do not use WinZip or a similar program to unpack the *.zip files. Please use the Siemens STEP7 software.

De-archiving the program examples

File De-archive Select archive (Internet download) HGPPI_Application.zip Open Select target directory OK De-archive: The de-archived data is stored in the project directory. OK De-archive: The following objects were de-archived. Do you want to open them now? Yes


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4. Select the corresponding hardware configuration and load it into your PLC: e.g. PLC 314C-2DP

5. Select the program: "Program example X" 6. Select the desired application and load the project into the controller

(the screenshot shows an example)

Target system Load Follow the instructions on the screen

7. Switch the mode selector to the RUN position


17 Festo HGPPI

1.4.5 Adapting the hardware configuration

If the hardware configuration in the sample project differs from your CPU or I/O module, then proceed as follows:

1. Create a new Step7 project. 2. Create a new station, e.g. "S7-300 station" and plan the hardware

configuration. 3. Copy the S7 program folder(s), e.g. "Program example1" into your project. 4. Make any required adjustments to the S7 program, such as e.g. the addresses

of the inputs or outputs. A modified hardware configuration can also project other address ranges if necessary change the system settings for addressing. With "symbolic" programming, the addressing in the S7 symbol table can be adapted. Then perform a consistency check of the modules. Please follow the instructions in the manual for your controller or the Siemens programming user interface.

Please observe the training systems for production and process automation from Festo Didactic. You can choose from a number of individual training media and courses.

Training media

Textbooks Basic principles of pneumatic control technology, programmable

logic controllers, basic level

Workbooks Programmable logic controllers, basic level fieldbus technology AS

interface/Profibus DP

Teaching materials Basic web-based training principles of electro-pneumatics

FluidSIM 4.0 Pneumatics

Courses

P111 Basic principles of pneumatics and electro-pneumatics

P121 Maintenance and troubleshooting on pneumatic and electro-pneumatic systems

S7-BASIS SIMATIC S7 Basic principles

S7-INTERM SIMATIC S7 Intermediate course

S7-BUS SIMATIC S7 Basic principles of bus technology

GRAFCET The new procedure description (DIN/EN 60848 standard)

You will find more training media on the Internet: http://www.festo-didactic.com

Note

Please refer to the current course programme for the venues, dates and prices.


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1.4.6 Overview of the modules

Every program example includes the following modules:

Modules of a program example in the Step7 project for the HGPPI

The modules FB10, DB5 and DB10 are required to control the HGPPI gripper. They concern the control of the nominal values for the gripper, the evaluation of the gripper's actual values and the list of commands. The controlling of the gripper is integrated into a new or existing project by copying/inserting the modules FB10 and DB5. The data module DB10 is created automatically (see the following table).

The other modules are for specific applications and are created automatically. The function of the application example is programmed in the function module FB1.


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Module Symbolic name Description Function

OB1 MAIN Organisation module Program control

OB82 I/O_FLT1 Error OB for monitoring errors of

modules capable of being diagnosed

Without OB82, the CPU switches to

STOP when an error occurs

OB86 RACK_FLT Error OB for monitoring errors of the

decentralised periphery

Without OB86, the CPU switches to

STOP when an error occurs

FB1 Example-specific Functional module for sample

application

Controlling the commands or command

sequence

FB10 HGPPI_CONTROL Function module

for controlling the HGPPI

Controlling the handshake

DB1 Instance data module for function

module FB1

The instance data module is created

automatically when function module

FB1 is called.

DB5 DB_COMMAND-LIST Global data module with records for

the user-specific gripper commands

Gripper commands can be entered as

records in the data module.

DB10 DB_HGPPI_CONTROL Instance data module for function

module "HGPPI_CONTROL"

The instance data module is created

automatically when the function

module "HGPPI_CONTROL" is called.

DB100 Test Global data module with operands for

controlling the functions of function

module FB1.

Information memory

HGPPI_Command-List HGPPI_Command-List Table of variables ONLINE view of the commands

HGPPI_OPERATE HGPPI_OPERATE Table of variables ONLINE view of the communication

OUTPUT_Data OUTPUT_Data Table of variables ONLINE view of the actual and nominal

values

SFC14 DPRD_DAT System function for the consistent

reading of data of a DP norm slave

Used in the function module

"HGPPI_CONTROL", is created

automatically

SFC15 DPWR_DAT System function for the consistent

transfer of data to a DP norm slave



automatically

SFC24 TEST_DB System function for receiving

information via a data module



automatically


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Assignment list Equipment identifier and addressing for Simatic S7-300 CPU314C-2DP

Name: Date:

Project name:

Digital outputs Sheet 1 of 3

Name

Equipment identifier

symbol

Address

Simatic CPU 313C/314C-2DP

Digital inputs

Pushbutton E0.0

Pushbutton E0.1

Pushbutton E0.2

Pushbutton E0.3

E0.4

E0.5

INIT pushbutton INIT E0.6

STOP pushbutton STOP E0.7

Digital outputs station

Lamp A0.0

Lamp A0.1

A0.2

A0.3

A0.4

A0.5

A0.6

A0.7


21 Festo HGPPI


Topic: Sequence control of the gripper

Description of problem: How can gripper fingers be opened and closed?

A workpiece is gripped. The Open and Close actions are selected with two binary input signals (E0.0 = OPEN, E0.1 = CLOSE). The current status is to be confirmed via binary output signals. Additional signal inputs can be used to initialise (E0.6 = INIT, Reset error) and stop (E0.7 = STOP, Stop_1, Stop_2) the gripper.

xOeff

xM

FF

xM

Befehl "ffnen" Befehl "Schlieen"

1.5 Program example 1 - Sequence control


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Handshake

In the sequence module FB1 of the Simatic Step7 program, the handshake between gripper and PLC master has been programmed for each command. The commands are predefined in a table of commands. The variable table "HGPPI_OPERATE" is used to parameterize the table of commands. A command consists of a function number, the activation of the gripper jaws (single- or double-jaw command) and four nominal values.

Start

ACK

MotionComplete

1 2

Handshake

In the first step, the command number is transferred to the function module FB10 "HGPPI_CONTROL" and the start signal is set. Before the second step is performed, the system waits for the "ACK" feedback signal from the gripper in order to reset the start signal. The command is executed and the "Motion Complete" signal is reset. The execution of the command is complete in the PLC program, when the "Motion Complete" feedback signal is sent back from one or both of the gripper jaws, depending on the single- or double-jaw command.


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Functions

An error reset deletes the error word in the event of an acknowledgeable error (E3.xx) and resets the error bit. A double-jaw stop is also performed. If there is no error, a command with function 1 acts in the same way as a double-jaw stop. The jaw bits in parameter P2.1 are ignored for function 1.

Parameter function 1: Error reset

Byte 3 Byte 4 Byte 5 Byte 6 Byte 7 Byte 8 Byte 9 Byte 10 Finger selection

1st parameter 2nd parameter 3rd parameter 4th parameter

Nominal values (data PLC gripper)

1)

Actual values (data gripper PLC)

Actual position finger 1

Actual position finger 2

Actual force finger 1

Actual force finger 2

P3.1 P3.2 P3.5 P3.6

1) Jaw specification is not evaluated

For the "Error reset" function, it is not necessary to transfer nominal value para-meters.

Function 1: Error reset


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xOeff

xM

The gripper jaws are positioned to a specified mid-position (xM) and a specified opening (xOeff).

Parameter function 35: Position to centre point and open




Desired mid-

position

Desired opening Position tolerance

factor

Select 1 = 1

Select 2 = 1

P2.4 P2.5 P2.8


Actual mid-

position

Actual opening Actual gripping

force

-

P3.3 P3.4 P3.7

Function 35: Position to centre point and open


25 Festo HGPPI

FFFF

xMxM

The gripper grips with a specified force (F) and the adjustment of the centre point (xM).

Parameter function 31: Force-controlled gripping with fixed mid-position




Nominal gripping

force

Desired mid-

position

Position tolerance

factor

Select 1 = 1

Select 2 = 1

P2.14 P2.4 P2.8


Actual mid-

position


force

-

P3.3 P3.4 P3.7

Function 31: Force-controlled gripping with fixed mid-position


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Commands and transfer values

Function DB5

"DB_COMMAND-List"

Command

transfer values

Explanation

1 Command 0

Error reset

Jaw_1 = 1, Jaw_2 = 1

Nominal value 1 = 0

Nominal value 2 = 0

Nominal value 3 = 0

Nominal value 4 = 0

Double-jaw command

No nominal values are

transferred or evaluated

35 Command 1

Open

Jaw_1 = 1, Jaw_2 = 1

Nominal value 1 = 0

Nominal value 2 = 2000


Nominal value 4 = 0

Double-jaw command

Desired mid-position

Desired opening

Position tolerance factor

-

31 Command 2

Force-controlled gripping

with fixed mid-position

Jaw_1 = 1, Jaw_2 = 1


Nominal value 2 = 0


Nominal value 4 = 0

Double-jaw command

Desired gripping force



-

(all values are "decimal")

In program example 6, function 35 is used with offset.


27 Festo HGPPI


Topic: Reading and writing parameters

Task: Which firmware does the HGPPI have?

When servicing is required, the user of the HGPPI should know the serial number and firmware status of the gripper. Function 4 "Read parameters" can be used to read these basic parameters of the gripper with command 4 from the list of com-mands (DB5). The Read and Write actions are activated with two binary input signals (E0.2 = READ, E0.3 = WRITE). Additional signal inputs can be used to initialise (E0.6 = Reset error) and stop (E0.7 = Stop_1, Stop_2) the gripper. The parameters for firmware (P1.17+1.18) and serial number (P1.19+1.20) are not included in the sys-tem parameters of the GSD file.

For application example 2, the basic parameters for the max. permitted force ramp F ( P 1.02) and the max. permitted speed vmax (P1.03) can be modified using command 5.

1.6 Program example 2 - Read/write parameters


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Functions

With this command, up to two parameters can be written simultaneously. If only one parameter is written, a "0" (zero) must be specified for the other parameter as a number (= "No.", byte 7). An entry in the subindex and value is then ignored. The values of the following parameters can be modified using function 3:

Parameter

number

Subindex Description

1 0..17 System parameters

Changes to the subindices 0 to 6 take effect immediately. Changes to the subindices 7 to 16 only take effect with the next command. The attempt to write into another parameter will result in an execution error E3.04. Please read the notes in the manual for the HGPPI, in the chapter: "Diagnosis and troubleshooting". The write command is triggered with the start flag in the normal manner. Both jaw bits must be set for this. It is completed when the HGPPI indicates "Motion Complete" (MC). If no error occurs during processing, the HGPPI transfers the written values as a res-ponse into the actual values. If an error occurs during processing, the error number is transferred instead of the value. At the same time, the HGPPI indicates a malfunction.

The entered values do not have any storage effect, i.e. with the reinitialisation, the initialisation values / default values are reactivated.

Parameter function 3: Write parameters




Parameter 1 Parameter 2 Select 1 = 1

Select 2 = 1 No. Subindex Value No. Subindex Value


Parameter 1 Parameter 2 -

No. Subindex Value No. Subindex Value

Function 3 Write parameters

Note

Attention


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With this command, up to two parameters can be read simultaneously. If only one parameter is read, a "0" (zero) must be specified for the other parameter as a num-ber (= "No.", byte 7). An entry in the subindex is ignored in this case. The values of the following parameters can be read using function 4:

Parameter

number

Subindex Description

1 0..20 System parameters

2 0, 2..16 Nominal values apart from

start byte

3 1..7 Actual values apart from

status word and error word

The attempt to read another parameter will result in an execution error (E3.05). The read command is triggered with the start flag in the normal manner. Both jaw bits must be set for this. It is completed when the HGPPI indicates Motion Complete (MC). If an actual value (parameter group 3) is read, only the value that applied at the time of the query is output. There is no automatic refreshing if the displayed value changes. If no error occurs during processing, the HGPPI transfers the desired values into the actual values as the response. If an error occurs during processing, the error number is transferred instead of the value. At the same time, the HGPPI indicates a malfunction.

Parameter function 4: Read parameters




Parameter 1 Parameter 2 Select 1 = 1

Select 2 = 1 Number Subindex Number Subindex


Parameter 1 Parameter 2 -

Number Subindex Value Number Subindex Value

Function 4: Read parameters


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Function DB5

"DB_COMMAND-List"

Command

transfer values

Explanation

1 Command 1

Error reset

Jaw_1 = 1, Jaw_2 = 1

Nominal value 1 = 0

Nominal value 2 = 0

Nominal value 3 = 0

Nominal value 4 = 0

Double-jaw command



4 Command 2

Read parameters

Jaw_1 = 1, Jaw_2 = 1

Nominal value 1 = W#16#0111

(hex)

Nominal value 2 = 0

nominal value 3 = W#16#0112

(hex)

Nominal value 4 = 0

Double-jaw command

Firmware high

-

Firmware low

-

3 Command 3

Write parameters

Jaw_1 = 1, Jaw_2 = 1


(hex)



(hex)


Double-jaw command

max. perm. force ramp

Default value (1..600)

max. perm. speed

Default value (1...200)

(all values are "decimal", unless otherwise defined)

To enter data, the data type (word) must be specified for S7 programming: "W#16#0111". W# Word format 16# Preset value in hexadecimal format

Note


31 Festo HGPPI

The return values can be determined with the S7 variable table "HGPPI_OPERATE".

The reading of the firmware resulted in the following actual values:

Actual value 1 0111h Firmware high Controller module version

Actual value 2 0105h V 1.09

Actual value 3 0112h Firmware high Communication module version

Actual value 4 0104h V 1.06

The actual values 1 and 3 show the requested parameters. The actual values 2 and 3 are evaluated for the version number of the firmware. The word "0106h" codes the version number to "1.06".


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The serial number of the HGPPI can be evaluated by the modification of the transfer values of command 3 with the following nominal values:

Function DB5

"DB_COMMAND-List"

Command

transfer values

Explanation

4 Command 1

Read parameters

Jaw_1 = 1, Jaw_2 = 1


(hex)

Nominal value 2 = 0


(hex)

Nominal value 4 = 0

Double-jaw command

Serial number high

-

Serial number low

-

The reading of the serial number resulted in the following actual values:

Actual value 1 0113h Serial number high

Actual value 2 51-00h "5 1" is equivalent to the production date 5 = 2005, 6=2006, ..., F = 2015 1 = January, 2 = February, ..., C = December "0 0" is added to the serial number

Actual value 3 0114h Serial number low

Actual value 4 001Fh "00 001Fh" is equivalent to the serial number "31"


33 Festo HGPPI


Topic: Workpiece detection

Task: How can the middle of the workpiece be detected or read?

A workpiece is to be gripped in the middle with the HGPPI gripper. The middle of the workpiece is to be read or programmed using a reference workpiece. In this way, the mid-position of the gripper is defined for all subsequent workpieces. The "Open" and "Close" actions can be selected with two binary input signals (E0.1 = OPEN, E0.2 = CLOSE). An additional input signal allows the middle of the workpiece to be programmed (E0.0 = CHECK). Additional signal inputs can be used to initialise (E0.6 = Reset error) and stop (E0.7 = STOP, Stop_1, Stop_2) the gripper.

F F?

Workpiece detection

The workpiece is to be gripped in a force-controlled manner with free mid-position using a double-jaw command function 30 (CHECK signal). The current actual position values for force-controlled gripping are read and written into a fixed command record of the list of commands in DB5 as nominal position values for a command for force-controlled gripping with fixed mid-position (function 30) and for opening (function 34). For prepositioning, the current actual opening is increased by +2 mm and applied as the desired position for function 34. The current actual position is applied as the desired mid-position for functions 31 and 34. The position tolerance factor is set permanently in FB3 for both functions to 100%. When the determination of the actual values is completed, the gripper is opened using function 10 (Position).

During operating cycles, the gripper can be prepositioned to the external dimension of the workpiece using function 34 (OPEN signal). The gripper is closed at the determined desired "mid"-position using function 31 (CLOSE signal).

1.7 Program example 3 - Workpiece detection


Festo HGPPI 34

Functions

FFFF

The gripper grips with a specified gripping force (F). Only the gripping force of the gripper is controlled. The position of the jaws can be moved freely.

Parameter function 30: Force-controlled gripping with fixed mid-position




Nominal gripping

force

Select 1 = 1

Select 2 = 1

P2.14


Actual mid-

position


force

-

P3.3 P3.4 P3.7

Function 30: Force-controlled gripping with freely movable mid-position


35 Festo HGPPI

FF F=0F=0

xOeff

xM xMxM

First, the gripping force (F) is reduced in a controlled manner along with the adjust-ment of the current mid-position (xM). Then the controller is switched to a position-ing of the gripper jaws to Open (xOeff) and Centre point (xM).

Parameter function 34: Open

Finger selection

Byte 3 Byte 4 Byte 5 Byte 6 Byte 7 Byte 8 Byte 9 Byte 10



Desired mid-

position

Desired opening Position tolerance

factor

Select 1 = 1

Select 2 = 1

P2.4 P2.5 P2.8


Actual mid-

position


force

-

P3.3 P3.4 P3.7

Function 34: Open


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Function DB5

"DB_COMMAND-List"

Command

transfer values

Explanation

1 Command 0

Error reset

Jaw_1 = 1, Jaw_2 = 1

Nominal value 1 = 0

Nominal value 2 = 0

Nominal value 3 = 0

Nominal value 4 = 0

Double-jaw command



30 Command 1


with free mid-position

Jaw_1 = 1, Jaw_2 = 1


Nominal value 2 = 0


Nominal value 4 = 0

Double-jaw command




-

10 Command 2

Open

Jaw_1 = 1, Jaw_2 = 1




Nominal value 4 = 0

Single-jaw command

Desired position finger 1

Desired position finger 2


-

31 Command 3



Jaw_1 = 1, Jaw_2 = 1


Nominal value 2 = actual value1

command 2


Nominal value 4 = 0

Double-jaw command




-

34 Command 4

Open

Jaw_1 = 1, Jaw_2 = 1


command 2


command 2


Nominal value 4 = 0

Double-jaw command


Desired opening


-


For intermediate storage, the return values of the HGPPI are read as actual values 1-4 of function 30 and transferred to the flag words MW40-46 (also see OB1, network 2).


37 Festo HGPPI


Topic: Reliable application of forces

Task: How can gripper fingers be positioned and gripping forces be applied?

A workpiece is to be gripped from a pallet. The gripper's movement range is limited. Therefore the gripper fingers need to be prepositioned. The Open, Close and Position actions are to be selected with three binary input signals (E0.0 = OPEN, E0.1 = CLOSE, E0.2 = POSITION). The current status is to be confirmed via binary output signals. Additional signal inputs can be used to initialise (E0.6 = INIT, Reset error) and stop (E0.7 = STOP, Stop_1, Stop_2) the gripper.

FF

Gripping with prepositioning

The gripper is to be opened (function 34) and gripped in a force-controlled manner using a double-jaw command (function 31). The gripper fingers of the HGPPI are prepositioned in an intermediate position using a single-jaw command (function 10) so that the handling system can move the gripper down into the pallet or the limited space of the workpieces.

If the gripper does not need to be moved down into a pallet or between workpieces, a command with function 32 can be used to preposition the gripper. Then the workpiece can be gripped.

1.8 Program example 4 - Reliable application of forces


Festo HGPPI 38

Function

X X X1 X2

Both jaws can be moved individually (if necessary also simultaneously) to a new desired position (X).

Parameter function 10: Position




Nominal position

finger 1

Position tolerance

factor

Select 1 = 1

Select 2 = 0

P2.2 P2.8

Nominal position

finger 2

Position tolerance

factor

Select 1 = 0

Select 2 = 1

P2.3 P2.8

Nominal position

finger 1

Nominal position

finger 2

Position tolerance

factor Select 1 = 1

Select 2 = 1

P2.2 P2.3 P2.8


Actual position

finger 1

Actual position

finger 2

Actual force

finger 1

Actual force

finger 2 -

P3.1 P3.2 P3.5 P3.6

Function 10: Position (single-jaw command)


39 Festo HGPPI


Function DB5

"DB_COMMAND-List"

Command

transfer values

Explanation

1 Command 0

Error reset

Jaw_1 = 1, Jaw_2 = 1

Nominal value 1 = 0

Nominal value 2 = 0

Nominal value 3 = 0

Nominal value 4 = 0

Double-jaw command



35 Command 1

Open

Jaw_1 = 1, Jaw_2 = 1

Nominal value 1 = 0



Nominal value 4 = 0

Double-jaw command


Desired opening


-

31 Command 2



Jaw_1 = 1, Jaw_2 = 1


Nominal value 2 = 0


Nominal value 4 = 0

Double-jaw command




-

10 Command 3

Position

Jaw_1 = 1, Jaw_2 = 1




Nominal value 4 = 0

Single-jaw command

Desired position jaw 1

Desired position jaw 2


-



Festo HGPPI 40


Topic: Travel speed

Task: How quickly can a gripped workpiece be moved?

A workpiece is to be gripped and moved. The Open and Move actions are to be selected with two binary input signals (E0.0 = OPEN, E0.1 = MOVE). The current status is to be confirmed via binary output signals. Additional signal inputs can be used to initialise (E0.6 = INIT, Reset error) and stop (E0.7 = STOP, Stop_1, Stop_2) the gripper.

The movement of the gripper jaws at constant speed (v), while the workpiece is grip-ped with a constant force (F, friction locking), is to be implemented with a gripping force that is below the maximum possible gripping force.

v

FFFF

Movement with force control

For the movement, the gripper jaws are position- and force-controlled simultane-ously, i.e. the pistons are moved via the differential pressure of the outer cylinder chambers and, at the same time, the pressure in the middle cylinder chamber is kept constant (see application example 1).

forcetravelforcefrictionstsaticpressuresupplytravelduringforceGripping

1.9 Program example 5 - Travel speed


41 Festo HGPPI

The gripper jaws are moved from the "actual mid-position" to the "desired mid-position". The speed can be specified with a speed factor of 1-100%. The speed factor is based on the system parameter "maximum permitted speed" that is defined in the GSD file or that can be changed using the "Write parameter" function (see application example 2). The coordinate system for the "desired mid-position" is positive in the direction of gripper jaw 1 and negative in the direction of gripper jaw 2. The workpiece geometry must be taken into account for the travel path:

distancegripper 2-widthworkpiece-opening max.travel max. =

The gripping distance is the minimum distance between the gripper fingers and the workpiece with open gripper fingers so that a handling station/robot can move the gripper without touching the workpiece:

Maximum opening = 20 mm Workpiece diameter = 10 mm Gripping distance = 0.5 mm

mm 9mm 0.52-mm 10-mm 20travel max. ==

0

1 2

+1000 -1000

+475

Sense of direction of the travel path (dimension: 0.01 mm)

If the workpiece geometry is changed, the travel data must be adapted in the program.

Attention


Festo HGPPI 42

Function

s

FFFF

xMxM

The gripper is moved to a specified mid-position (xM) along with the adjustment of the gripping force (F). A speed factor (s) is specified for this, which defines the percentage of the maximum speed for the movement.

When function 33 is completed, the speed factor is reset to 100% as the default value for all other functions.

Parameter function 33: Force-controlled movement




Nominal gripping

force

Desired mid-

position

Position tolerance

factor

Speed factor Select 1 = 1

Select 2 = 1

P2.14 P2.4 P2.8 P2.9


Actual mid-

position


force

-

P3.3 P3.4 P3.7

Function 33: Force-controlled movement


43 Festo HGPPI


Function DB5

"DB_COMMAND-List"

Command

transfer values

Explanation

1 Command 0

Error reset

Jaw_1 = 1, Jaw_2 = 1

Nominal value 1 = 0

Nominal value 2 = 0

Nominal value 3 = 0

Nominal value 4 = 0

Double-jaw command



35 Command 1

Positioning to centre

point and opening

Jaw_1 = 1, Jaw_2 = 1

Nominal value 1 = 0



Nominal value 4 = 0

Double-jaw command


Desired opening


-

31 Command 2



Jaw_1 = 1, Jaw_2 = 1


Nominal value 2 = 0


Nominal value 4 = 0

Double-jaw command




-

33 Command 3

Force-controlled

movement

Jaw_1 = 1, Jaw_2 = 1





Double-jaw command




Speed factor

33 Command 4

Force-controlled

movement

Jaw_1 = 1, Jaw_2 = 1


Nominal value 2 = -475


Nominal value 4 = 5

Double-jaw command




Speed factor

33 Command 5

Force-controlled

movement

Jaw_1 = 1, Jaw_2 = 1





Double-jaw command




Speed factor



Festo HGPPI 44


Topic: Internal gripping

Task: How can a workpiece be gripped with an internal gripper?

A workpiece is to be gripped with an internal gripper. The Open and Close actions are to be selected with two binary input signals (E0.0 = OPEN, E0.1 = CLOSE).

F F

Application example - Internal gripper

The internal gripper has a symmetrical offset to the centre point of the gripper jaws. The current status is to be confirmed via binary output signals. Additional signal inputs can be used to initialise (E0.6 = INIT, Reset error) and stop (E0.7 = STOP, Stop_1, Stop_2) the gripper.

01 2

A B

Internal gripper with symmetrical offset, e.g. A = B = 65 mm

The symmetrical offset of the internal gripper is 65 mm for each gripper finger. The complete opening between the gripper fingers is 130 mm.

The gripper's return value provides the actual opening of the gripper fingers as the actual value. The user can use it to adapt the coordinate system to the geometry of the gripper fingers.

1.10 Program example 6 - Internal gripping


45 Festo HGPPI

In the example, the actual opening of the gripper fingers shows the actual opening range of the gripper fingers as the return value from the HGPPI: with open gripper fingers, i.e. the internal gripper moves the gripper fingers

together, an actual opening of 130 mm is displayed (equivalent to a return value of "13000"),

with closed gripper fingers, i.e. the internal gripper moves the gripper fingers apart, an actual opening of approx. 150 mm is displayed (equivalent to a return value of "15000").

With internal gripping, the gripping force has an outward effect, i.e. in the opposite direction of external gripping. That is why, with internal gripping, the parameter for the desired gripping force is displayed with a negative sign. In the example, a desired gripping force of 30N (equivalent to a default value of "-300") is specified.

Actual opening return value

Gripping force for internal gripping


Festo HGPPI 46

Modify the offset system parameters P07 and P08 in the properties of the DP slave in the hardware configuration.

Hardware configuration Step7 DP slave

For parameter P07: offset jaw 1 and P08: "6500" is entered for offset jaw 2. "Save and translate" the hardware configuration and load it into the controller.

After modifying the offset parameters, the user must change the default values for the desired opening in relation to the offset parameters!

Change the offset parameters for jaws 1 and 2 back to the default values "0" after completing the performance test in "programming example 6"!

Attention


47 Festo HGPPI


Function DB5

"DB_COMMAND-List"

Command

transfer values

Explanation

1 Command 0

Error reset

Jaw_1 = 1, Jaw_2 = 1

Nominal value 1 = 0

Nominal value 2 = 0

Nominal value 3 = 0

Nominal value 4 = 0

Double-jaw command



35 Command 1

Position to centre point

and open

Jaw_1 = 1, Jaw_2 = 1

Nominal value 1 = 0



Nominal value 4 = 0

Double-jaw command


Desired opening


-

31 Command 2



Jaw_1 = 1, Jaw_2 = 1

Nominal value 1 = -300

Nominal value 2 = 0


Nominal value 4 = 0

Double-jaw command




-



Festo HGPPI 48


Topic: Sequence with graph7

Task: Demo program

The sequence of the program commands can also be solved with graph7. The sequence processes 10 commands in succession as demo program. The commands can be modified in the variable table: "HGPPI_Command-List".

1.11 Program example 7 - Step sequence

49 Festo HGPPI

Applying forces .............................. 37

Assignment list .............................. 20

Basic parameters ........................... 10

CPU ................................................ 14

De-archiving................................... 15

Displacement encoder ..................... 7

Double-jaw command .................... 11

Error reset ...................................... 26

Force control ........................ 8, 40, 43

Force ramp ..........................10, 27, 30

Graph7 ........................................... 48

Gripping force for internal gripping ......................................... 45

Gripping force regulation ................. 7

Gripping forces................................. 7

GSD file .......................................... 41

Handshake..................................... 22

Internal gripper .............................. 44

Load voltage .................................. 12

Logic voltage.................................. 12

MMC............................................... 14

Mode selector ................................ 15

Motion Complete ........................... 22

Offset ............................................. 44

Position control................................ 7

Power supply ................................. 12

Reading parameters....................... 27

Sequence ....................................... 48

Sequence control ........................... 21

Speed............................................. 10

Speed factor................................... 41

Speed profile.................................. 11

Table of variables........................... 22

Tolerance position ......................... 10

Travel speed................................... 40

Workpiece detection ...................... 33

Index


Festo HGPPI 50

HGPPI Applikationsbeispiele V9 En

Documents

hgppi application examples

program examples

contents contents festo

parallel gripper hgppi

intended use

local festo service

reliable application

basic requirements