Download 1771-2.71, Allen-Bradley Analog Input Module, Product Data

Product Data
Analog Input Module
ALLENBRADLEY
Analog Input Module
(Cat. No. 1771-IFE)
Product Data
Description
Your analog input module senses up to 16 single-ended or 8 differential
analog signals at its inputs and converts them to a proportional four-digit
BCD or twelve-bit binary value. You can select from five voltage or three
current input ranges. Each voltage input is software selectable on a per
channel basis. Each current input is hardware selectable on a per channel
basis. This allows interface between a programmable controller and several
types of analog devices such as those measuring temperature, pressure,
RPM, light intensity and position. All outputs of these devices should
conform to the voltage or current range selected for each module input
channel.
You can use your module with any programmable controller using the
1771 I/O structure with block-transfer capability. Block-transfer
programming moves up to 20 channel and module status words from the
module’s memory to a designated area in the processor data table in a
single scan (block-transfer-read) or up to 37 module configuration words
from the data table to module memory (block-transfer-write).
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Product Data
Analog Input Module
Conversion of the analog input value to a 4-digit BCD or twelve-bit binary
format sets the resolution of the module to 1 part in 4095. This defines the
number of units available to the module in dividing up its particular
voltage or current range. The BCD or binary value from each input channel
is contained in a 16-bit input data word that is stored in the module’s
memory.
Features
High density – 16 single-ended or 8 differential inputs on one card
User program selectable input ranges on a per channel basis
Selectable scaling to engineering units
Selectable digital filtering
Selectable Real-Time Sampling (Rev F or later)
No external power required
Input Channels
Your analog input module accepts up to 16 single-ended or 8 differential
input signals. The single-ended or differential option is software selectable
for voltage inputs. Current inputs also require insertion of a current link
configuration plug (figure 1) before the module is installed in a 1771 I/O
rack.
All inputs for a particular module must be either single-ended or
differential input signals. You can configure individual inputs to operate
with any one of five voltage or three current input ranges (tables A and B).
The module has input overvoltage protection to 200V rms (continuous).
Exceeding this limit may damage the module. However, 1500V
opto-electrical isolation protects the rest of the system from damage due to
overvoltage or overcurrent at the module’s inputs. We give nominal
voltage and current specifications in the specifications section and tables A
and B.
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Product Data
Analog Input Module
Figure 1
Location of Current Link Configuration Plugs
Data Transfer
A write-block-transfer instruction moves up to 37 module configuration
words from the processor data table to the module’s memory. A
read-block-transfer instruction moves up to 20 input and module status
words from the module’s memory to a designated area in the data table.
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Product Data
Analog Input Module
Table A
Input Voltage Ranges
Nominal
Voltage
Range
Corresponding
4Digit BCD
Output Range
Corresponding
12Bit Binary
Output Range
Volts
Per
Bit
+1 to +5V
0 to +5V
-5 to +5V
0 to +10V 1
-10 to +10V
0000 to +4095
0000 to +4095
-4095 to +4095
0000 to +4095
-4095 to +4095
0000 to +4095
0000 to +4095
-4095 to +4095
0000 to +4095
-4095 to +4095
0.98mV
1.22mV
1.22mV
2.44mV
2.44mV
1 0 to +10 VDC range configurable using bipolar scaling
Table B
Input Current Ranges2
Nominal
Current
Range
Corresponding
4Digit BCD
Output Range
Corresponding
12Bit Binary
Output Range
Current
Per
Bit
0 to +20mA
+4 to +20mA
-20 to +20
0000 to +4095
0000 to +4095
-4095 to +4095
0000 to +4095
0000 to +4095
-4095 to +4095
.0049mA
.0039mA
.0049mA
2 selected by current mode configuration plug
WriteBlockTransfer
You can select channel ranges using words #1 and #2 of the
write-block-transfer instruction (refer to figure 2). Each channel is
represented by two bits.
Use word #3 of the write-block-transfer instruction to select data format
(BCD or binary), input type (single-ended or differential), real-time sample
period and the digital filter value.
Digital Filtering
You can apply digital filtering to analog input signals to reduce the effects
of electrical noise. The digital filter equation uses an input filter time
constant that is user selectable. Bits 00 through 07 of word 3 of the
write-block-transfer instruction represent the digital filter time constant
value (.00 BCD-no filter to .99 BCD-maximum filter).
RealTime Sampling
The Real-Time Sampling (RTS) mode of operation provides data from a
fixed time period for the processor to use. Your module must be Series A,
revision F or later to use the RTS feature.
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Product Data
Analog Input Module
In the RTS mode the module scans and updates its inputs at a user defined
time interval (DT). Themodule ignores block-transfer-read (BTR) requests
for data until the sample time period elapses.
Set bits 13 through 17, word 3 in the block-transfer-write (BTW) data file
to enable the RTS mode. You can select RTS periods ranging from 100
milliseconds to 3.1 seconds.
Scaling
Your module can perform linear conversion of raw data to engineering
units, for example; gallons/minute, degrees C/degrees F, and pounds/square
inch. Unscaled data in the input module has a range of 0 through 4095 or
–4095 through +4095 depending on the input range selected. The
resolution of this data is 12-bit binary corresponding to one part in 4095.
The resolution of scaled values is the same as for raw data, one part in
4095, regardless of the chosen scale. You can scale each input channel
independent of the other channels.
Figure 2
Word Assignments for WriteBlockTransfer
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Product Data
Analog Input Module
Implement the scaling feature by selecting the sign (+ or –) for minimum
scaling values using word #4, bits 00 through 17 of the write block transfer
instruction (reset, or 0 = +; set, or I = –). Select the sign (+ or –) for
maximum scaling values using word #5, bits 00 through 17. Use word #6
through #37 of the write-block-transfer instruction to enter the minimum
and maximum scaling values for each of the 16 channels (refer to figure 2).
BCD format is –9999 to +9999. You must enter the scaling values in BCD
whether or not you read the inputs in BCD. You can find the scaled input
values in words 5 through 20 of the read-block-transfer instruction (figure
3).
ReadBlockTransfer
The read-block-transfer instruction (figure 3) supplies diagnostic and data
information to the processor. Word #1 provides power-up and valid data
status. Words #2, #3 and #4 provide channel data status (i.e. under-range
condition, over-range condition and polarity). Words #5 through #20
provide actual data for channels 1 through 16.
Diagnostics
Your module has diagnostic features that monitor internal communication
and memory processes for faults. If an on-board self test fault occurs,
block-transfers are inhibited, the red fault (FLT) LED (figure 4) lights and
the green run (RUN) LED goes off. Figure 3 shows the word assignments
for the read-block-transfer instruction. The diagnostics word (word #1) is
the first data word in the read-block-transfer file for transfer to the central
processor. It contains a power-up bit (bit 00) that is set when the module is
first powered up. It is reset after a write-block-transfer. It also contains an
under-range or over-range bit (bit 01) that is set when any input is under or
over-range and an invalid scaling data bit (bit 02) that is set when you enter
invalid minimum or maximum scaling values.
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Product Data
Analog Input Module
Figure 3
Word Assignments for ReadBlockTransfer
Figure 4
Module Diagnostic Indicators
Power Requirements
System power is supplied through the I/O chassis backplane. The module
requires a maximum of 750mA at 5V from the backplane. Total this
amount with the current requirements of other modules in the rack to avoid
overloading the supply or exceeding the backplane capacity. You must
consider the power usage of all modules in the I/O chassis.
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Product Data
Analog Input Module
Wiring
CAUTION: Remove system power before removing or
installing your module in the 1771 I/O chassis. Failure to
remove system power could result in damage to module
circuitry.
Make connections to your input module through the wiring arm (cat. no.
1771-WG) shipped with the module. Attach the wiring arm to the pivot bar
at the bottom of the I/O chassis. It pivots upward and connects with the
module so you can install or remove the module without disconnecting the
wires (figure 5). Figures 6 and 7 show connections to the wiring arm for 16
single-ended inputs and 8 differential inputs, respectively.
Figure 5
Field Wiring Arm Connections
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Product Data
Analog Input Module
Figure 6
Input Module Connections for 16 Singleended Inputs
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Product Data
Analog Input Module
Figure 7
Input Module Connections for 8 Differential Inputs
Recommended maximum cable length for voltage-mode input devices is
50 feet. This recommendation is based on considerations of signal
degradation and electrical noise immunity in typical industrial
environments. Cable length for current-mode input devices is not as
restrictive because analog signals from these devices are less sensitive to
electrical noise interference.
When using shielded cable, ground the foil shield and drain wire at one
end of the cable, only. We recommend that you wrap the foil shield and
drain wire together and connect them to a chassis mounting bolt. At the
opposite end of the cable, tape any exposed shield or drain wire to insulate
it from electrical contact.
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Product Data
Analog Input Module
WARNING: Remove power from the 1771-I/O chassis backplane
and wiring arm before removing or installing an I/O module.
Failure to remove power from the backplane or wiring arm could cause
module damage, degradation of performance, or injury.
Failure to remove power from the backplane could cause injury or
equipment damage due to possible unexpected operation.
Module Location
Electrostatic Discharge
Place your module in any I/O module slot of the I/O chassis except for the
extreme left slot. This slot is reserved for PC processors or adapter
modules. We recommend the following:
1.
Do not put the module in the same module group as a discrete high
density module. However, you can put other single slot modules in
the same module group.
2.
Do not put the module close to AC or high voltage DC I/O modules,
to minimize electrical noise and temperature effects. You can
minimize noise by grouping input and output modules together within
an I/O chassis.
Electrostatic discharge can damage integrated circuits or semiconductors in
this module if you touch backplane connector pins. It can also damage the
module when you set configuration plugs and/or switches inside the
module. Avoid electrostatic damage by observing the following
precautions:
Touch a grounded object to discharge yourself before handling the
module.
Do not touch the backplane connector or connector pins.
If you configure or replace internal components, do not touch other
circuit components inside the module. If available, use a static-safe
work station.
When not in use, keep the module in its static-shield bag.
CAUTION: Electrostatic discharge can degrade performance
or damage the module. Handle as stated above.
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Product Data
Analog Input Module
Keying
Plastic keying bands, shipped with each I/O chassis, provide an easy
method for keying I/O slots to accept only one type of module. We
strongly recommend that you use them.
The module is slotted in two places on the rear edge of the circuit board.
The position of the keying bands on the backplane connector must
correspond to these slots to allow insertion of the module. You can key any
connector in an I/O chassis to receive this module except for the left-most
connector reserved for adapter or processor modules. Place keying bands
between the following numbers labeled on the backplane connector:
Between 10 and 12
Between 24 and 26
You may change the position of these bands if subsequent system design
and rewiring makes insertion of a different type of module necessary. Use
needle-nose pliers to insert or remove keying bands.
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Product Data
Analog Input Module
Specifications
Inputs per Module
G 16 singleended or 8
differential
Module Location
G Single slot in 1771 I/O
chassis
Input Voltage Ranges
(nominal)
G +1 to +5V DC
G 0 to 5 V DC
G 5 to +5V DC
G 10 to +10V DC
Input Current Ranges
(nominal)
G +4 to +20 mA
G 0 to +20 mA
G 20 to +20 mA
Resolution
G 12bit binary
Accuracy
G +0.1% of range
@ 25°C
Linearity
G +1 LSB
Repeatability
G +1 LSB
Maximum Input Voltage
G +15V
Input Impedance
G 1000 M Ohms for voltage
ranges
G 250 Ohms for current ranges
Common Mode Rejection
G 80 db, DC120Hz
Environmental Conditions
G Operational Temperature:
0 to 60°C (32 to 140°F)
G Storage Temperature:
40 to 85°C (40 to 185°F)
G Relative Humidity:
5 to 95% (without
condensation)
Keying
Current Requirements
G 750 mA at 5 V from I/O chassis
backplane
G Between 10 and 12
G Between 24 and 26
BCD and Binary Output to
Processor
G 0000 to 409510 for +1 to +5 V,0
to +5V, 0 to +10V, 0 to +20
mA, +4 to +20 mA input ranges
G 409510 to 409510 for +5V, +10
V, +20 mA input ranges
G Monotonic output with no
Engineering Units Sent to
Processor
G +9999 BCD with selectable
scaling
Internal Scan Rate
A/D Converter
missing codes
G Resolution: 12bit binary
G Absolute accuracy: +0.1% of
full scale
G Quantizing error +1/2LSB
G Temperature Coefficient:
+50ppm/°C of full scale range
for 0°C to 60°C ambient
G Recalibration time: check
calibration at 6 month
intervals to maintain specified
accuracy
G 12.5 milliseconds for 8
differential inputs (no scaling
or digital filtering)
G 25 milliseconds for 16
singleended inputs (no
scaling or digital filtering)
OptoElectrical Isolation
G 1500 V (transient)
Input Overvoltage
Protection
G 200V
1987 Allen-Bradley Company, Inc.
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Product Data
Analog Input Module
With offices in major cities worldwide
WORLD
HEADQUARTERS
Allen-Bradley
1201 South Second Street
Milwaukee, WI 53204 USA
Tel: (1) 414 382-2000
Telex: 43 11 016
FAX: (1) 414 382-4444
EUROPE/MIDDLE
EAST/AFRICA
HEADQUARTERS
Allen-Bradley Europe B.V.
Amsterdamseweg 15
1422 AC Uithoorn
The Netherlands
Tel: (31) 2975/43500
Telex: (844) 18042
FAX: (31) 2975/60222
Publication 1771-2.71 — April 1987
Supersedes Publication 1771-2.71 — May 1985
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As a subsidiary of Rockwell International, one of the world’s largest technology
companies — Allen-Bradley meets today’s challenges of industrial automation with over
85 years of practical plant-floor experience. More than 11,000 employees throughout the
world design, manufacture and apply a wide range of control and automation products
and supporting services to help our customers continuously improve quality, productivity
and time to market. These products and services not only control individual machines but
integrate the manufacturing process, while providing access to vital plant floor data that
can be used to support decision-making throughout the enterprise.
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HEADQUARTERS
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Limited
Room 1006, Block B, Sea
View Estate
28 Watson Road
Hong Kong
Tel: (852) 887-4788
Telex: (780) 64347
FAX: (852) 510-9436
CANADA
HEADQUARTERS
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Limited
135 Dundas Street
Cambridge, Ontario N1R
5X1
Canada
Tel: (1) 519 623-1810
FAX: (1) 519 623-8930
LATIN AMERICA
HEADQUARTERS
Allen-Bradley
1201 South Second Street
Milwaukee, WI 53204 USA
Tel: (1) 414 382-2000
Telex: 43 11 016
FAX: (1) 414 382-2400
PN 955102-17
Printed in USA