A Smart Sensor Interface for Industrial Monitoring using ARM
2014-15
A Smart Sensor Interface for Industrial Monitoring using ARM
2014-15
CHAPTER 1INTRODUCTION1.1 IntroductionIntelligent wireless
sensor-based controls have drawn attention of the industry on
account of reduced costs, better power management, ease in
maintenance, and effortless deployment in remote and hard-to-reach
areas. They have been successfully deployed in many industrial
applications such as maintenance, monitoring, control, security,
etc. In this research, the focus is on the issues of portability,
reliability, flexibility and robustness while using wireless
connectivity in industrial applications such as instrumentation and
predictive maintenance, and to design a workable solution. This
project expanding the scope of the applications, investigate design
choices for the proposed system, and presents detailed experimental
results of the implementations with their analysis. The proposed
Smart Sensor Platform is an attempt to develop a generic platform
with plug-and-play capability to support hardware interface,
payload and communication needs of multiple sensors, and actuators.
An RF link (ZigBee) facilitates communications in a point-to-point
topology. The design also provides means to update operating,
monitoring parameters, operational thresholds, and sensor and RF
link specific firmware modules over-the-air. It is composed of two
main components a sensor-wireless hardware interface and system
integration framework, which facilitates the defining of
interaction between sensors based on process needs. The
intelligence necessary to process the sensor signals, monitor the
functions against defined operational templates, and enable
swapping of sensor and RF link, resides on the microcontroller of
the hardware interface.A variety of industrial sensors
(temperature, Gas detection, colour change and light etc.) have
been interfaced and successfully tested with the platform. The
organization of this project covers potential industrial
applications to benefit by wireless connectivity, and the supply
chain management.1.2 Literature surveyWireless technology is a
constantly evolving area, especially for industrial users, which
often makes wireless infrastructure deployments in industrial
environments difficult. Before taking on such a project, facility
operators need to be aware of the challenges from rapid prototyping
of wireless sensors in an industrial environment and the best
practices for radio frequency (RF) design in complex or harsh RF
environments, such as manufacturing, industrial, or power
generation facilities.The business drivers for this type of project
can most often be associated with the transition from
conditioned-based monitoring to performance-based monitoring. In
addition, the data points are usually collected manually, and the
lack of continuous data does not allow for complex analytics or
modelling.Implementing wireless sensor sets create benefits across
multiple areas. For instance, scarce engineering resources can
focus on data analysis rather than data collection from disparate
sources and can concentrate on few degrading trends rather than
every trend. Maintenance workers can reduce or entirely eliminate
selected data collection rounds through placement of wireless
monitoring sensors. The need for deep technical capabilities
on-site and concerns about inconsistent diagnostic results due to
experience levels of individual employees can be greatly reduced.By
leveraging wireless technologies, operators can acquire critical
component monitoring data in significantly higher volumes, reduce
staff impact of making collection rounds, and focus those resources
on data analysis and prognostics of issues. By implementing a
wireless infrastructure and using it for the rapid deployment of
new sensor types, operators can create significant advances in
critical component monitoring.1.3 Problem StatementIn any
industrial process there may be one or more physical quantities are
to be measured simultaneously. In such cases it is required to take
reading of their values at regular interval and for that a person
has to seat there and monitor it continuously. If there are so many
such processes then they require more man power. This is really
wastage of human power. Also the premises where the actual process
runs may be hazardous or may be uncomfortable for mankind. To send
these values using pair of wires and connections but in that case
there will be a complex network of lots of wires that may lead to
chaos.1.4 Scope of the ProjectTo monitor all these physical
quantities from central control room where hardly two or three
persons can easily monitor all the sensors, stores and update the
records. All the physical quantities that are measured at one
place, their values are sent wirelesslyto a remote location.The
values are sent at regular intervals. Their values are displayed at
both ends without change. Along with there are indication for
changing in values. So this system is also useful in taking some
decisions. So let us see how the concept is utilized.
CHAPTER 2A Smart Sensor Interface for Industrial Monitoring
using ARMIntelligent wireless sensor-based controls have drawn
attention of the industry on account of reduced costs, better power
management, ease in maintenance, and effortless deployment in
remote and hard-to-reach areas. They have been successfully
deployed in many industrial applications such as maintenance,
monitoring, control, security, etc. In this research, the focus is
on the issues of portability, reliability, flexibility and
robustness while using wireless connectivity in industrial
applications such as instrumentation and predictive maintenance,
and to design a workable solution.
NODE SECTION
Fig 2.1 Node sectionMONITORING SECTION
ZIGBEEPC
Fig 2.2 Monitoring SectionThe block diagram shows transmitter
side of the system. As shown in the block diagram, system needs,
ARM LPC2129 controller, 2x16 LCD, buzzer, ZigBee module, CO2 sensor
and a colour sensor. LCD is used to display data, Buzzer is used to
alert the user in case of high temperature, co2 sensor is used to
detect excessive carbon element and colour sensor detects colours
(only fundamental colours) finally ZigBee to transmit all measured
values. Functional description of system is as follows:
Initially, to measure the temperature and light values,
temperature sensor, LDR and is used. Temperature sensor will be
connected to channel 0 of ADC and LDR will be connected to Channel
1 of ADC module which is built in in controller. Digital conversion
of these two analog inputs will be done and result will collected
and displayed on the LCD. Later, status of CO2 sensor as well as
COLOUR sensor will be checked and displayed on the LCD. COLOUR
sensor works in 3 different modes i.e., RED, GREEN and BLUE mode.
In RED mode, red colour will be having higher frequency than any
other colour, similarly in GREEN mode green colour will be having
higher frequency and in BLUE mode blue colour will be having higher
frequency, thus based on frequencies COLOUR sensor will detect the
colours. If temperature goes higher than the specified value a
buzzer will become on for sometimes to alert user. Finally, all the
measured data, status of CO2 and colour will be transmitted through
ZigBee using serial communication with the baud rate of 9600.
In Receiver side values will be received through ZigBee and
displayed on the screen thus the system can be monitored.
2.1 LPC2129 MICROCONTROLLERThe LPC2129 are based on a 16 bit
ARM7TDMI-SCPU with real-time emulation and embedded trace support,
together with 128 kilobytes (kB) of embedded high speed flash
memory. A 128-bit wide memory interface and unique accelerator
architecture enable 32-bit code execution at maximum clock rate.
For critical code size applications, the alternative 16-bit Thumb
Mode reduces code by more than 30 % with minimal performance
penalty.With their compact 64 pin package, low power consumption,
various 32-bit timers, 4-channel 10-bit ADC, 2 advanced CAN
channels, PWM channels and 46 GPIO lines with up to 9 external
interrupt pins these microcontrollers are particularly suitable for
automotive and industrial control applications as well as medical
systems and fault-tolerant maintenance buses. With a wide range of
additional serial communications interfaces, they are also suited
for communication gateways and protocol converters as well as many
other general-purpose applications. The features of the lpc2129
microcontroller is given below:
16/32-bit ARM7TDMI-S microcontroller in a tiny LQFP64 package.
16 kB on-chip Static RAM. 128/256 kB on-chip Flash Program Memory.
128-bit wide interface/accelerator enables high speed 60 MHz
operation. In-System Programming (ISP) and In-Application
Programming (IAP) via on-chip boot-loader software. Flash
programming takes 1ms per 512 byte line. Single sector or full chip
erase takes 400ms. Embedded ICE-RT interface enables breakpoints
and watch points. Interrupt service routines can continue to
execute while the foreground task is debugged with the on-chip Real
Monitor software. Embedded Trace Macro cell enables non-intrusive
high speed real-time tracing of instruction execution. Two
interconnected CAN interfaces with advanced acceptance alters. Four
channel 10-bit A/D converter with conversion time as low as 2.44ms.
Multiple serial interfaces including two UARTs (16C550), Fast C
(400 Kbits/s) and two SPIs 60 MHz maximum CPU clock available from
programmable on-chip Phase-Locked Loop with settling time of 100ms.
Vectored Interrupt Controller with configurable priorities and
vector addresses. Two 32-bit timers (with four capture and four
compare channels), PWM unit (six-outputs), Real Time Clock and
Watchdog. Single-chip 16/32-bit microcontrollers Up to forty-six 5
V tolerant general purpose I/O pins. Up to nine edge or level
sensitive external interrupt pins available. On-chip crystal
oscillator with an operating range of 1 MHz to 30 MHz Two low power
modes, Idle and Power-down. Processor wake-up from Power-down mode
via external interrupt. Individual enable/disable of peripheral
functions for power optimization.Architecture of LPC2129 is given
below:
Fig 2.1.1 Block Diagram
The LPC2129 consists of an ARM7TDMI-S CPU with emulation
support, the ARM7 Local Bus for interface to on-chip memory
controllers, the AMBA Advanced High-performance Bus (AHB) for
interface to the interrupt controller, and the VLSI Peripheral Bus
(VPB, a compatible superset of ARMs AMBA Advanced Peripheral Bus)
for connection to on-chip peripheral functions. The LPC2129
configures the ARM7TDMI-S processor in little-endian byte order.AHB
peripherals are allocated a 2 megabyte range of addresses at the
very top of the 4 gigabyte ARM memory space. Each AHB peripheral is
allocated a 16 kilobyte address space within the AHB address space.
LPC2129 peripheral functions (other than the interrupt controller)
are connected to the VPB bus. The AHB to VPB bridge interfaces the
VPB bus to the AHB bus. VPB peripherals are also allocated a 2 MB
range of addresses, beginning at the 3.5 GB address point. Each VPB
peripheral is allocated a 16 kilobyte address space within the VPB
address space.The connection of on-chip peripherals to device pins
is controlled by a Pin Connection Block. This must be configured by
software to fit specific application requirements for the use of
peripheral functions and pins.LPC2129
Fig 2.1.2 Pin Diagram of LPC2129.
The LPC2129 incorporate a 256 kB Flash memory system. This
memory may be used for both code and data storage. Programming of
the Flash memory may be accomplished in several ways: over the
serial built-in JTAG interface, using In System Programming (ISP)
and UART0, or by means of In Application Programming (IAP)
capabilities. The application program, using the In Application
Programming (IAP) functions, may also erase and/or program the
Flash while the application is running, allowing a great degree of
flexibility for data storage field firmware upgrades, etc.The
LPC2129 provide a 16 kB static RAM memory that may be used for code
and/or data storage. The SRAM supports 8-bit, 16-bit, and 32-bit
accesses. The SRAM controller incorporates a write-back buffer in
order to prevent CPU stalls during back-to-back writes. The
write-back buffer always holds the last data sent by software to
the SRAM. This data is only written to the SRAM when another write
is requested by software (the data is only written to the SRAM when
software does another write). If a chip reset occurs, actual SRAM
contents will not reflect the most recent write request (i.e. after
a "warm" chip reset, the SRAM does not reflect the last write
operation). Any software that checks SRAM contents after reset must
take this into account. Two identical writes to a location
guarantee that the data will be present after a Reset.
Alternatively, a dummy write operation before entering idle or
power-down mode will similarly guarantee hat the last data written
will be present in SRAM after a subsequent Reset.
2.2 LM35 Precision Centigrade Temperature Sensors
The LM35 series are precision integrated-circuit temperature
sensors, with an output voltage linearly proportional to the
Centigrade temperature. Thus the LM35 has an advantage over linear
temperature sensors calibrated in Kelvin, as the user is not
required to subtract a large constant voltage from the output to
obtain convenient Centigrade scaling. The LM35 does not require any
external calibration or trimming to provide typical accuracies of C
at room temperature and C over a full 55C to +150C temperature
range. Low cost is assured by trimming and calibration at the wafer
level. The low output impedance, linear output, and precise
inherent calibration of the LM35 make interfacing to readout or
control circuitry especially easy. The device is used with single
power supplies, or with plus and minus supplies. As the LM35 draws
only 60 A from the supply, it has very low self-heating of less
than 0.1C in still air. The LM35 is rated to operate over a 55C to
+150C temperature range, while the LM35C is rated for a 40C to
+110C range (10 with improved accuracy). The LM35 series is
available packaged in hermetic TO transistor packages, while the
LM35C, LM35CA, and LM35D are also available in the plastic TO-92
transistor package. The LM35D is also available in an 8-lead
surface-mount small outline package and a plastic TO-220
package.
The FEATURES of LM35 is given below: Calibrated Directly in
Celsius (Centigrade) Linear + 10 mV/C Scale Factor 0.5C Ensured
Accuracy (at +25C) Rated for Full 55C to +150C Range Suitable for
Remote Applications Low Cost Due to Wafer-Level Trimming Operates
from 4 to 30 V Less than 60-A Current Drain Low Self-Heating, 0.08C
in Still Air Nonlinearity Only C Typical Low Impedance Output, 0.1
for 1 mA Load
Fig 2.2.1 LM35 Temperature Sensor
The LM35 is applied easily in the same way as other
integrated-circuit temperature sensors. Glue or cement the device
to a surface and the temperature should be within about 0.01C of
the surface temperature.This presumes that the ambient air
temperature is almost the same as the surface temperature. If the
air temperature were much higher or lower than the surface
temperature, the actual temperature of the LM35 die would be at an
intermediate temperature between the surface temperature and the
air temperature, which is especially true for the TO-92 plastic
package where the copper leads are the principal thermal path to
carry heat into the device, so its temperature might be closer to
the air temperature than to the surface temperature.To minimize
this problem, ensure that the wiring to the LM35, as it leaves the
device, is held at the same temperature as the surface of interest.
The easiest way to do this is to cover up these wires with a bead
of epoxy which will insure that the leads and wires are all at the
same temperature as the surface, and that the temperature of the
LM35 die is not affected by the air temperature.The Parameters of
the LM35 is given by:
Table 2.1
2.3 LIGHT DEPENDENT RESISTOR (LDR Sensor)A Light-dependent
resistor (LDR) or photocell is a light-controlled variable
resistor. The resistance of a photo-resistor decreases with
increasing incident light intensity; in other words, it exhibits
photoconductivity. A photo-resistor can be applied in
light-sensitive detector circuits, and light- and dark-activated
switching circuits.A photo-resistor is made of a high resistance
semiconductor. In the dark, a photo-resistor can have a resistance
as high as a few meg-ohms (M), while in the light, a photo-resistor
can have a resistance as low as a few hundred ohms. If incident
light on a photo-resistor exceeds a certain frequency, photons
absorbed by the semiconductor give bound electrons enough energy to
jump into the conduction band. The resulting free electrons (and
their whole partners) conduct electricity, thereby lowering
resistance. The resistance range and sensitivity of a
photo-resistor can substantially differ among dissimilar devices.
Moreover, unique photo-resistors may react substantially
differently to photons within certain wavelength bands.
Fig 2.3.1 LDR symbol and material used
A photoelectric device can be either intrinsic or extrinsic. An
intrinsic semiconductor has its own charge carriers and is not an
efficient semiconductor, for example, silicon. In intrinsic devices
the only available electrons are in the valence band, and hence the
photon must have enough energy to excite the electron across the
entire bandgap. Extrinsic devices have impurities, also called
dopants, added whose ground state energy is closer to the
conduction band; since the electrons do not have as far to jump,
lower energy photons (that is, longer wavelengths and lower
frequencies) are sufficient to trigger the device. If a sample of
silicon has some of its atoms replaced by phosphorus atoms
(impurities), there will be extra electrons available for
conduction. This is an example of an extrinsic
semiconductor.Photo-resistors are less light-sensitive devices than
photodiodes or phototransistors: the two latter components are true
semiconductor devices, while a photo-resistor is a passive
component and does not have a PN-junction. The photo-resistivity of
any photo-resistor may vary widely depending on ambient
temperature, making them unsuitable for applications requiring
precise measurement of or sensitivity to light.Photo-resistors also
exhibit a certain degree of latency between exposure to light and
the subsequent decrease in resistance, usually around 10
milliseconds. The lag time when going from lit to dark environments
is even greater than, often as long as one second. This property
makes them unsuitable for sensing rapidly flashing lights, but is
sometimes used to smooth the response of audio signal compression.
The LDR characteristic curve is shown below:
Fig 2.3.2 resistance VS Illumination
The cell resistance increases with increasing light intensity
Light dependent resisters have a particular property in that they
remember the lighting conditions in which they have been stored.
This memory effect can be minimised by storing LDRs in light prior
to use. Light storage reduces equilibrium time to reach steady
resistance values.
2.4 MQ-7 (CO2)A carbon dioxide sensor or CO2 sensor is an
instrument for the measurement of carbon dioxide gas. The most
common principles for CO2 sensors are infrared gas sensors (NDIR)
and chemical gas sensors. Measuring carbon dioxide is important in
monitoring indoor air quality, the function of the lungs in the
form of a capnograph device, and many industrial processes.Chemical
CO2 gas sensors with sensitive layers based on polymer- or
heteropolysiloxane have the principal advantage of very low energy
consumption, and can be reduced in size to fit into
microelectronic-based systems. On the downside, short- and long
term drift effects as well as a rather low overall lifetime are
major obstacles when compared with the NDIR measurement principle.
Most CO sensors are fully calibrated prior to shipping from the
factory. Over time, the zero point of the sensor needs to be
calibrated to maintain the long term stability of the sensor.
Fig 2.4.1 MQ-7 (CO2)The surface resistance of the sensor Rs is
obtained through effected voltage signal output of the load
resistance RL which series-wound. The relationship between them is
described: Rs\RL = (Vc-VRL) / VRL
Fig 2.4.2 Graph of CO2 SensorFig. 2.4.2 shows alterable
situation of RL signal output measured by using Fig 2.4.3 circuit
output signal when the sensor is shifted from clean air to carbon
Dioxide (CO2) output signal measurement is made within one or two
complete heating period (2.5 minute from high voltage to low
voltage).Sensitive layer of MQ-7 gas sensitive components is made
of SnO2 with stability, so, it has excellent long term stability.
Its service life can reach 5 years under using condition. The
feature of the MQ-7 is given by:
High sensitivity to carbon dioxide. Stable and long life.
The STANDARD CIRCUIT OF MQ-7 as shown in below Fig 2.4.3
Fig 2.4.3 standard measuring circuit of MQ-7The sensitive
components consist of 2 parts. One is heating circuit having time
control function (the high voltage and the low voltage work
circularly). The second is the signal output circuit; it can
accurately respond changes of surface resistance of the sensor.
Resistance value of MQ-7 is difference to various kinds and
various concentration gases. So, when using these components,
sensitivity adjustment is very necessary. We recommend that you
calibrate the detector for 200ppm CO in air and use value of Load
resistance that (RL) about 10 K (5K to 47 K). When accurately
measuring, the proper alarm point for the gas detector should be
determined after considering the temperature and humidity
influence. The sensitivity adjusting program: a. Connect the sensor
to the application circuit. b. Turn on the power; keep preheating
through electricity over 48 hours. c. Adjust the load resistance RL
until you get a signal value which is respond to a certain carbon
monoxide concentration at the end point of 90 seconds. d. Adjust
the another load resistance RL until you get a signal value which
is respond to a CO concentration at the end point of 60 seconds .
The application of MQ-&: They are used in gas detecting
equipment for carbon monoxide (CO) in family and industry or
car.
2.5 COLOR LIGHT-TO-FREQUENCY CONVERTERThe TCS3200 programmable
colour light-to-frequency converters that combine configurable
silicon photodiodes and a current-to-frequency converter on a
single monolithic CMOS integrated circuit. The output is a square
wave (50% duty cycle) with frequency directly proportional to light
intensity (irradiance). The full-scale output frequency can be
scaled by one of three pre-set values via two control input pins.
Digital inputs and digital output allow direct interface to a
microcontroller or other logic circuitry. Output enable (OE) places
the output in the high-impedance state for multiple-unit sharing of
a microcontroller input line. In the TCS3200, the
light-to-frequency converter reads an 8 x 8 array of photodiodes.
Sixteen photodiodes have blue filters, 16 photodiodes have green
filters, 16 photodiodes have red filters, and 16 photodiodes are
clear with no filters.The four types (colours) of photodiodes are
interdigitated to minimize the effect of non-uniformity of incident
irradiance. All photodiodes of the same colour are connected in
parallel. Pins S2 and S3 are used to select which group of
photodiodes (red, green, blue, clear) are active. Photodiodes are
110m x 110m in size and are on 134m centres.
Fig 2.5.1 Colour sensorThe features of colour Sensor is given
below: High-Resolution Conversion of Light Intensity to Frequency
Programmable Colour and Full-Scale Output Frequency Communicates
Directly With a Microcontroller Single-Supply Operation (2.7 V to
5.5 V) Power down Feature Nonlinearity Error Typically 0.2% at 50
kHz Stable 200 ppm/C Temperature Coefficient Low-Profile Lead (Pb)
Free and RoHS Compliant Surface-Mount Package
Fig 2.5.2 Colour sensor functional block diagram.
The Application of Colour Sensor is given below: Power supply
considerations Power-supply lines must be decoupled by a 0.01-F to
0.1-F capacitor with short leads mounted close to the device
package. Input interface A low-impedance electrical connection
between the device OE pin and the device GND pin is required for
improved noise immunity. All input pins must be either driven by a
logic signal or connected to VDD or GND they should not be left
unconnected (floating). Output interface The output of the device
is designed to drive a standard TTL or CMOS logic input over short
distances. If lines greater than 12 inches are used on the output,
a buffer or line driver is recommended. A high state on Output
Enable (OE) places the output in a high-impedance state for
multiple-unit sharing of a microcontroller input line. Power
downPowering down the sensor using S0/S1 (L/L) will cause the
output to be held in a high-impedance state. This is similar to the
behaviour of the output enable pin, however powering down the
sensor saves significantly more power than disabling the sensor
with the output enable pin.
Photodiode type (colour) selection The type of photodiode (blue,
green, red, or clear) used by the device is controlled by two logic
inputs, S2 and S3.
Output frequency scaling Output-frequency scaling is controlled
by two logic inputs, S0 and S1. The internal light-to-frequency
converter generates a fixed-pulsewidth pulse train. Scaling is
accomplished by internally connecting the pulse-train output of the
converter to a series of frequency dividers. Divided outputs are
50%-duty cycle square waves with relative frequency values of 100%,
20%, and 2%. Because division of the output frequency is
accomplished by counting pulses of the principal internal
frequency, the final-output period represents an average of the
multiple periods of the principle frequency. The output-scaling
counter registers are cleared upon the next pulse of the principal
frequency after any transition of the S0, S1, S2, S3, and OE lines.
The output goes high upon the next subsequent pulse of the
principal frequency, beginning a new valid period. This minimizes
the time delay between a change on the input lines and the
resulting new output period. The response time to an input
programming change or to an irradiance step change is one period of
new frequency plus 1 s. The scaled output changes both the
full-scale frequency and the dark frequency by the selected scale
factor. The frequency-scaling function allows the output range to
be optimized for a variety of measurement techniques. The
scaled-down outputs may be used where only a slower frequency
counter is available, such as low-cost microcontroller, or where
period measurement techniques are used. The choice of interface and
measurement technique depends on the desired resolution and data
acquisition rate. For maximum data-acquisition rate,
period-measurement techniques are used. Pin diagram and description
of colour sensor pin numbres is show in fig 2.15 and table 2.1
respectively.
Fig 2.5.3 Pin diagram of colour sensor.
Pin Function Descriptions PinPin name Pin Description
1GNDPower supply ground.
2OUT Output frequency
3S2Photodiode type selection inputs.
4S3Photodiode type selection inputs.
5VCCSupply Voltage.2.7-5v
6VCC Supply Voltage.2.7-5v
7S1Output frequency scaling selection inputs.
8S0Output frequency scaling selection inputs.
9LED LED CONTROL 1:ON,0:OFF
10GND Power supply ground
Table 2.2 Pin Function Descriptions
Output data can be collected at a rate of twice the output
frequency or one data point every microsecond for full-scale
output. Period measurement requires the use of a fast reference
clock with available resolution directly related to reference clock
rate. Output scaling can be used to increase the resolution for a
given clock rate or to maximize resolution as the light input
changes. Period measurement is used to measure rapidly varying
light levels or to make a very fast measurement of a constant light
source. Maximum resolution and accuracy may be obtained using
frequency-measurement, pulse-accumulation, or integration
techniques. Frequency measurements provide the added benefit of
averaging out random- or high-frequency variations (jitter)
resulting from noise in the light signal. Resolution is limited
mainly by available counter registers and allowable measurement
time. Frequency measurement is well suited for slowly varying or
constant light levels and for reading average light levels over
short periods of time. Integration (the accumulation of pulses over
a very long period of time) can be used to measure exposure, the
amount of light present in an area over a given time period.
2.6 ZIGBEEZigbee modules (Tarang modules) are designed with low
to medium transmit power and for high reliability wireless
networks. The modules require minimal power and provide reliable
delivery of data between devices. The interfaces provided with the
module help to directly fit into many industrial applications. The
modules operate within the 2.4-2.4835 GHz frequency band with IEEE
802.15.4 baseband. A feature of Zigbee is as follows:
Range - Indoor/Urban: up to 300 mts. Range - Outdoor line of
sight: up to 50kms with directional antenna. Transmit Power: up to
1 watt / 30 dBm nominal. Receiver Sensitivity: up to 107 dBm. RF
data rate: 250 kbps. AT Command Modes for configuring Module
Parameters Direct sequence spread spectrum technology. Analog to
digital conversion and digital I/O line support. Tarang can be
interfaced with a micro controller or a PC using serial port with
the help of appropriate level conversion.
Fig2.6.1 Interfacing ZigBee Module
Specification of the Tarang is given in the following table
2.3:
General
Operating FrequencyISM 2.4 GHz
Indoor/Urban rangeUp to 100ml with 2db antennas
Transmit Power output19dbm Typical
RF data rate250 Kbps
Antenna OptionsMMCX Connector, Chip Antenna, Wire Antenna
Table2.4 Specification of the Tarang
Power
Supply Voltage (vcc)3.3 to 3.6v
Transmit Current120mA
Idle/receive Current65mA
Power-down