Spectrum Controls 1746sc-INI4vi User Manual
Owner’s Guide 0300127-04 Rev. F
™
SLC 500
A
NALOG
Catalog Numbers
1746sc-INI4i
1746sc-INI4vi
I
I
SOLATED
NPUT
M
ODULES
Important Notes
1. Read all the information in this guide before installing the product.
2. The information in this owner's guide applies to hardware and
software version 1.0 or later.
3. This guide assumes that the reader has a full working knowledge of
the relevant processor.
Notice
The products and services described in this owner's guide are useful in a
wide variety of applications. Therefore, the user and others responsible
for applying the products and services described herein are responsible
for determining their acceptability for each application. While efforts
have been made to provide accurate information within this owner's
guide, Spectrum Controls assumes no responsibility for the accuracy,
completeness, or usefulness of the information herein.
Under no circumstances will Spectrum Controls be responsible or liable
for any damages or losses, including indirect or consequential damages
or losses, arising out of either the use of any information within this
owner's guide or the use of any product or service referenced herein.
No patent liability is assumed by Spectrum Controls with respect to the
use of any of the information, products, circuits, programming, or
services referenced herein.
The information in this owner's guide is subject to change without notice.
Limited W arranty
Spectrum Controls warrants that its products are free from defects in
material and workmanship under normal use and service, as described in
Spectrum Controls literature covering this product, for a period of 1 year.
The obligations of Spectrum Controls under this warranty are limited to
replacing or repairing, at its option, at its factory or facility, any product
which shall, in the applicable period after shipment, be returned to the
Spectrum Controls facility, transportation charges prepaid, and which
after examination is determined, to the satisfaction of Spectrum Controls,
to be thus defective.
This warranty shall not apply to any such equipment which shall have
been repaired or altered except by Spectrum Controls or which shall have
been subject to misuse, neglect, or accident. In no case shall the liability
of Spectrum Controls exceed the purchase price. The aforementioned
provisions do not extend the original warranty period of any product
which has either been repaired or replaced by Spectrum Controls.
Table Of Contents
Preface
Who Should Use This Guide........................................................................3
What This Guide Covers ..............................................................................3
Related Allen-Bradley Documents............................................................... 3
Terms & Abbreviations You Should Know ....................................................4
Overview & Specifications
Installing And Wiring Your
Module
Things To Consider Before
Using Y our Module
Using Your Input Module
Chapter 1
General Features And Benefits....................................................................7
Detailed Specifications.................................................................................8
Chapter 2
Avoiding Electrostatic Damage.................................................................. 12
Determining Power Requirements............................................................. 12
Selecting A Rack Slot ................................................................................13
Inserting Your Module Into The Rack ......................................................... 13
Wiring Y our Module ....................................................................................14
Chapter 3
How The Processor Communicates With Your Module.............................. 19
The Difference Between Channel Update Time & Step Response Time... 21
Selecting An Input Filter Frequency........................................................... 22
Auto-Calibration Time ................................................................................25
Channel Enable And Disable Times .........................................................25
Your Module’s Response To Slot Disabling................................................26
Chapter 4
Entering Your Module’s ID Code ................................................................27
Configuring Each Input Channel ................................................................ 28
Setting The User-Defined Scale Limits (optional) ......................................33
Monitoring Each Input Channel .................................................................35
Checking Each Input Channel’s Configuration And Status ........................35
Programming Examples
Testing Y our Module
Chapter 5
PID Control ................................................................................................39
User-Defined Scaling................................................................................. 41
Chapter 6
Inspecting Y our Module ..............................................................................43
Disconnecting Prime Movers .....................................................................44
Powering Up...............................................................................................44
Interpreting The LED Indicators .................................................................45
Interpreting I/O Error Codes ......................................................................45
Troubleshooting..........................................................................................46
ii SLC 500™ Isolated Analog Input Modules
Maintaining Your Module
And Ensuring Safety
Chapter 7
Preventive Maintenance.............................................................................47
Safety Considerations................................................................................47
Verifying Calibration
Index
Figures
Appendix A
Recommended Schedule .......................................................................... 49
Verifying Current Inputs .............................................................................49
Verifying Voltage Inputs (-INI4vi only) ........................................................50
Service....................................................................................................... 50
....................................................................................................... 51
Figure 1. Wiring diagrams (showing differential inputs). ............................16
Figure 2. Wiring schematic for 2-, 3-, and 4-wire analog inputs ................. 18
Figure 3. Wiring schematic for single-ended analog inputs........................18
Figure 4. Image table for your isolated analog input module .....................20
Figure 5. Channel update time and full-scale step response time .............21
Figure 6. Signal attenuation with 50 Hz input filter..................................... 23
Figure 7. Signal attenuation with 60 Hz input filter..................................... 24
Figure 8. Signal attenuation with 250 Hz input filter................................... 24
Figure 9. Signal attenuation with 500 Hz input filter................................... 25
Figure 10. Graph of signal value vs data value .......................................... 34
Figure 11. PID control example.................................................................. 39
Figure 12. Programming for PID control example. .....................................40
Figure 13. Data table for PID control example. ..........................................40
Figure 14. User-defined scaling example................................................... 41
Figure 15. Programming for user-defined scaling example........................41
Figure 16. Data table for user-defined scaling example.............................41
Figure 17. LED block..................................................................................45
Figure 18. Problem resolution flowchart .................................................... 46
Tables
Table 1. Related Allen-Bradley documentation ............................................4
Table 2. Electrical specifications—module ...................................................8
Table 3. Electrical specifications—inputs .....................................................9
Table 4. Physical specifications..................................................................10
Table 5. Environmental specifications ........................................................10
Table 6. Backplane current consumed .......................................................12
Table 7. Input module terminal block connections......................................17
Table 8. Cut-off frequency, step response time, & effective resolution....... 22
Table 9. Channel update time ....................................................................23
Table 10. Auto-calibration time per channel ...............................................25
Table 11. Channel enable and disable times..............................................25
Table 12. Module ID codes.........................................................................27
Table 13. Input channel configuration word (O:e.0 through O:e.3).............29
Table 14. Data format definitions................................................................31
Table 15. Input channel status word (I:e.4 through I:e.7) ...........................36
Table 16. LED definition .............................................................................45
Who Should Use This
Guide
Preface
Read this preface to familiarize yourself with the rest of the owner’s
guide. This preface covers:
• who should use this guide
• what this guide provides
• related Allen-Bradley documents
• terms & abbreviations you should know
Use this guide if you design, install, program, or maintain a control
system that uses Allen-Bradley Small Logic Controllers.
You should have a basic understanding of SLC 500 products. You should
also understand electronic process control and the ladder program
instructions required to generate the electronic signals that control your
application. If you do not, contact your local Allen-Bradley
representative for the proper training before using these products.
What This Guide Covers
Related Allen-Bradley
Documents
This guide covers the 1746sc-INI4i and 1746sc-INI4vi isolated analog
input modules. It contains the information you need to install, wire, use,
and maintain these modules. It also provides diagnostic and
troubleshooting help should the need arise.
Table 1 lists several Allen-Bradley documents that may help you as you
use these products.
4 SLC 500™ Isolated Analog Input Modules
Table 1. Related Allen-Bradley documentation
Allen-Bradley Doc. No. Title
1747-2.30 SLC 500 System Overview
SGI-1.1 Application Considerations for Solid State Controls
1770-4.1 Allen-Bradley Programmable Controller Grounding and
1747-6.2 Installation & Operation Manual for Modular Hardware
1747-NI001 Installation & Operation Manual for Fixed Hardware Style
1747-6.4 Allen-Bradley Advanced Programming Software (APS)
1747-6.11 Allen-Bradley Advanced Programming Software (APS)
1747-6.3 Getting Started Guide for Advanced Programming
Wiring Guidelines
Style Programmable Controllers
Programmable Controllers
User Manual
Reference Manual
Software (APS)
Terms & Abbreviations
You Should Know
ABT-1747-TSG001 SLC 500 Software Programmers’s Quick Reference
Guide
1747-NP002 Allen-Bradley HHT (Hand-Held Terminal) User Manual
1747-NM009 Getting Started Guide for HHT (Hand-Held Terminal)
SD499 Allen-Bradley Publication Index
AG-7.1 Allen-Bradley Industrial Automation Glossary
To obtain a copy of any of the Allen-Bradley documents listed, contact
your local Allen-Bradley office or distributor.
You should understand the following terms and abbreviations before
using this guide. For the definitions of terms not listed here, refer to
Allen-Bradley’s Industrial Automation Glossary, Publication AG-7.1
A/D – Refers to analog-to-digital conversion. The conversion produces a
digital value whose magnitude is proportional to the instantaneous
magnitude of an analog input signal.
Attenuation – The reduction in magnitude of a signal as it passes
through a system. The opposite of gain.
Channel – Refers to one of the sets of signal interfaces available on a
module’s terminal block.
Channel update time – For analog inputs, the time required for a
channel to sample and convert signals and make the resulting data
available to the processor. For analog outputs, the time required for the
Preface 5
channel to convert the data received from the processor to analog output
signals at the terminals.
Chassis – See rack.
Common mode rejection – The maximum level to which a common
mode input voltage appears in the numerical value read by the processor,
expressed in dB.
Common mode rejection ratio (CMRR) – The ratio of a device’s
differential voltage gain to common mode voltage gain. Expressed in dB,
CMRR is a comparative measure of a device’s ability to reject
interference caused by a voltage common to its terminal relative to
ground.
Common mode voltage – The voltage difference between the negative
terminal and analog common during normal differential operation.
Common mode voltage range – The largest voltage difference allowed
between either the positive or negative terminal and analog common
during normal differential operation.
Configuration word – Contains the channel configuration information
needed by the module to configure and operate each channel. Information
is written to the configuration word through the logic supplied in your
ladder program.
Cut-off frequency – The frequency at which the input signal is
attenuated 3 dB by the digital filter. Frequency components of the input
signal that are below the cut-off frequency are passed with under 3 dB of
attenuation for low-pass filters.
dB (decibel) – A logarithmic measure of the ratio of two signal levels.
Data scaling - The data format that you select to define the logical
increments of the channel data word.
Data word – A 16-bit integer that represents the value of the analog input
channel. The channel data word is valid only when the channel is enabled
and there are no channel errors.
Differential operation – The difference in voltage between a channel’s
positive and negative terminals.
Effective resolution – The number of bits in the channel data word that
do not vary due to noise.
Filter frequency – The user-selectable first-notch frequency for the A/D
converter’s digital filter. The digital filter provides high noise rejection at
the selected frequency.
Full-scale error (gain error) – The difference in slope between the
actual and ideal analog transfer functions.
6 SLC 500™ Isolated Analog Input Modules
Full-scale range (FSR) – The difference between the maximum and
minimum specified analog values.
Gain drift – The change in full-scale transition voltage measured over
the operating temperature range of the module.
LSB (least significant bit) – The bit that represents the smallest value
within a string of bits. The “weight” of this value is defined as the fullscale range divided by the resolution.
Maximum differential voltage – The largest voltage difference allowed
between the negative terminal and positive terminal during normal
differential operation.
Module ID code – A unique number associated with each 1746 I/O
module. The code defines for the processor the type of I/O or specialty
module residing in a specific slot in the 1746 chassis.
Module update time – See channel update time.
Normal mode rejection (differential mode rejection) – A logarithmic
measure, in dB, of a device’s ability to reject noise signals between or
among circuit signal conductors, but not between the equipment
grounding conductor or signal reference structure and the signal
conductors.
Overall accuracy – The worst-case deviation of the signal over the full
range, expressed in percent of full scale.
Rack – A hardware assembly that houses devices such as I/O modules,
adapter modules, processor modules, and power supplies.
Repeatability – The closeness of agreement among repeated
measurements of the same variable under the same conditions.
Resolution – The smallest detectable change in a measurement, typically
expressed in engineering units (e.g. 0.15 °C) or as a number of bits. For
example, a 12-bit system has 4096 possible output states. It can therefore
measure 1 part in 4096. See also effective resolution.
Sampling time – The time required by the A/D converter to sample an
input channel.
Status word – Contains status information about the channel’s current
configuration and operational state. You can use this information in your
ladder program to determine whether the channel data word is valid.
Step response time – The time required for the A/D signal to reach 95%
of its expected, final value, given a full-scale step change in the input
signal.
Useful resolution – See effective resolution.
Chapter
Overview And Specifications
The 1746sc-INI4i monitors up to 4 isolated analog current inputs, while
the 1746sc-INI4vi monitors up to 4 isolated analog current or voltage
inputs (selectable by channel). In both modules, you can select different
input ranges (for example, 4–20 mA or 1–5 Vdc) independently, by
channel, for optimal use of rack space.
Read this chapter to familiarize yourself further with your isolated analog
module. This chapter covers:
• general features and benefits
• detailed specifications
1
General Features And
Benefits
Increased Accuracy and Reliability
Both modules provide 750 Vdc channel-to-channel isolation, which
means no electrical crosstalk between channels (resulting in less noise
and a high effective resolution). They also provide 750 Vdc field wiringto-backplane isolation to protect your processor and other rack
components. And for state-of-the-art precision, they offer 16-bits of
resolution.
For added reliability, both modules perform a battery of diagnostic tests
at startup and can alert you to open input circuits through status bits and
LEDs. The open-circuit response state is selectable. Onboard overvoltage and over-current protection also help prevent damage to the
module due to wiring errors.
Reduced System Costs
Because channel-to-channel isolation is built into these modules, they
eliminate the need for expensive, external analog isolation blocks and the
time and space required to install them. Both modules provide a singleslot solution for applications requiring up to 4, mixed, analog inputs.
They also feature auto-calibration, so you never have to perform this
time-consuming task.
8 SLC 500™ Isolated Analog Input Modules
State-of-the-Art Performance
These modules incorporate proprietary Allen-Bradley technology, so they
operate and perform like the latest high-performance Allen-Bradley
products for full compatibility. Four selectable filter frequencies are
provided for signal/noise optimization. For even greater convenience,
they are fully configured through software (no DIP switches), can alert
the processor to a variety of errors through status bits, and can scale input
signals to user-defined ranges without any ladder programming.
Detailed Specifications
Table 2. Electrical specifications—module
Backplane Current Consumption (typical)
1746sc-INI4i 440 mA @ 5 Vdc
0 mA @ 24 Vdc
1746sc-INI4vi 550 mA @ 5 Vdc
0 mA @ 24 Vdc
Backplane Power Consumption (typical) 2.75 W
Number Of Channels 4 (differential, individually isolated)
I/O Chassis Location Any 1746 I/O module slot except slot 0
A/D Conversion Method Sigma-Delta
Input Filtering Programmable notch filters
Normal Mode Rejection 98 dB @ 50 Hz
(between + and - inputs) 98 dB @ 60 Hz
Common Mode Rejection 99 dB @ 1 kHz, 25 °C
(between inputs and chassis ground)
Calibration Factory calibrated
Autocalibrated every 10 sec (when enabled)
Opto-Electrical Isolation (10 sec) 750 Vdc channel-to-channel
750 Vdc field wiring-to-backplane
Module ID Code
1746sc-INI4i 3522
1746sc-INI4vi 3520
Thermal Dissipation 3.25 W maximum
Chapter 1: Overview And Specifications 9
Table 3. Electrical specifications—inputs
Input Current Ranges 4 to 20 mA
(selectable for each channel) 0 to 20 mA
Input Voltage Ranges—INI4vi only
(selectable for each channel) -10 to +10 Vdc
0 to 10 Vdc
0 to 5 Vdc
1 to 5 Vdc
SLC Communication Formats
(selectable for each channel) Scaled engineering units
Scaled for PID
Proportional counts
1746-NI4 format
User-defined scale A
User-defined scale B
Input Impedance
Current Inputs Less than 250 Ω
Voltage Inputs—INI4vi only Greater than 220 kΩ
Input Overcurrent Protection 70 mA non-continuous
33 mA continuous
Input Overvoltage Protection—INI4vi only 50 Vdc continuous
Input Filter 3 dB Cut-Off Frequencies 13.1 Hz for 50 Hz filter
(selectable for each channel) 15.7 Hz for 60 Hz filter
65.5 Hz for 250 Hz filter
131 Hz for 500 Hz filter
Input Step Response Time 80 ms for 50 Hz filter
66.7 ms for 60 Hz filter
16 ms for 250 Hz filter
8 ms for 500 Hz filter
Channel Update Time (minimum)
Current Inputs 14 ms with 500 Hz filters and all channels enabled
Voltage Inputs—INI4vi only 18 ms with 500 Hz filters and all channels enabled
Input Resolution (maximum) 16-bit
Current Inputs 312.8 nA/count
Voltage Inputs—INI4vi only 312.8 µV/count
Overall Accuracy
Current Inputs 0.15% of full scale @ 25 °C
0.25% of full scale @ 60 °C
Voltage Inputs—INI4vi only 0.10% of full scale @ 25 °C
0.25% of full scale @ 60 °C
Overall Drift
Current Inputs Offset: ±539 nA/°C
Gain: ±50.5 ppm/°C
Voltage Inputs—INI4vi only Offset: ±352 µV/°C
Gain: 34.8 ppm/°C
10 SLC 500™ Isolated Analog Input Modules
Table 4. Physical specifications
LED Indicators Four green channel status indicators, one for each channel
Recommended Cable Belden 8761 (shielded, twisted-pair) or equivalent
Wire Size (maximum) One 12–24 AWG wire per terminal
Terminal Block Removable (supplied)
Table 5. Environmental specifications
Operating Temperature 0 to 60 °C (32 to 140 °F)
Storage Temperature -40 to 85 °C (-40 to 185 °F)
Relative Humidity 5 to 95% non-condensing
Certifications UL/CUL and CE
Hazardous Environment Classifications Class I Division 2
One green module status indicator
Chapter
2
Installing And Wiring Your Module
Read this chapter to install and wire your module. This chapter covers:
• avoiding electrostatic damage
• determining power requirements
• selecting a rack slot
• inserting your module into the rack
• wiring your module
Note that although your module has a jumper on its printed circuit board,
this jumper is for the manufacturer’s use only, so do not alter its position.
Also, your module was calibrated by the manufacturer, so you don’t need
to perform this task. You may, however, want to verify the calibration
periodically using the procedures provided in Appendix A.
The following documents contain information that may help you as you
install and wire your module:
• NFPA 79, Electrical Standard for Industrial Machinery, published by
the National Fire Protection Association of Boston, MA
• National Electrical Code, published by the National Fire Protection
Association of Boston, MA
• IEEE Standard 518-1977, Guide for the Installation of Electrical
Equipment to Minimize Electrical Noise Inputs to Controllers from
External Sources
• IEEE Standard 142-1982, Recommended Practices for Grounding of
Industrial and Commercial Power Systems
• Noise Reduction Techniques in Electronic Systems, by Henry W. Ott;
published by Wiley-Interscience of New York in 1976
12 SLC 500™ Isolated Analog Input Modules
Avoiding Electrostatic
Damage
Guard against electrostatic damage by observing the following
precautions:
CAUTION
!
ELECTROSTATICALLY SENSITIVE COMPONENTS
• Before handling the module, touch a grounded object to
rid yourself of electrostatic charge.
• When handling the module, wear an approved wrist strap
grounding device.
• Handle the module from the front, away from the
backplane connector. Do not touch backplane
connector pins.
Determining Power
Requirements
• Keep the module in its static-shield container when not
in use or during shipment.
Failure to observe these precautions can degrade the module’s
performance or cause permanent damage.
The backplane of the SLC 500 system can provide both 5 Vdc and 24
Vdc power. The following table shows the current consumed by your
module when using these power sources:
Table 6. Backplane current consumed
Catalog Number 5 Vdc 24 Vdc
1746sc-INI4i 440 mA typical 0 mA
1746sc-INI4vi 550 mA typical 0 mA
Use this table to calculate the total load on the system power supply. For
more information, see the system Installation and Operation Manual.
Important — Your module does not supply power for input devices. You
must supply the appropriate power.
Chapter 2: Installing And Wiring Your Module 13
Selecting A Rack Slot
Inserting Y our Module
Into The Rack
Two factors determine where you should install your module in the rack:
ambient temperature and electrical noise. When selecting a slot for your
module, try to position your module:
• in a rack close to the bottom of the enclosure (since hot air rises)
• away from modules that generate significant heat, such as 32-point
input/output modules
• in a slot away from ac or high-voltage dc modules, hard contact
switches, relays, and ac motor drives
• away from the rack power supply (if using a modular system)
Remember that in a modular system, the processor always occupies the
first slot of the first rack.
CA UTION
!
POSSIBLE EQUIPMENT OPERATION
Before installing or removing your module, always
disconnect power from the SLC 500 system and from any
other source to the module (in other words, don’t “hot
swap” your module), and disconnect any devices wired to
the module.
Failure to observe this precaution can cause unintended
equipment operation and damage.
When inserting your module into the rack, you do not need to remove the
supplied 16-position terminal block from the module. If, however, you do
remove the terminal block, apply the supplied write-on label to the
terminal block, and use the write-on label to identify your module’s
location.
To remove the terminal block, unscrew the two retaining screws at the
top and bottom of the terminal block, and using needle-nose pliers,
carefully pry the terminal block loose.
To insert your module into the rack, follow these steps:
1. Align the circuit board of your module with the card guides at the top
and bottom of the chassis.
14 SLC 500™ Isolated Analog Input Modules
2. Slide your module into the chassis until both top and bottom retaining
clips are secure. Apply firm even pressure on your module to attach it
to its backplane connector. Never force your module into the slot.
Cover all unused slots with the Card Slot Filler, Allen-Bradley part
number 1746-N2.
To remove your module, press the retaining clips at the top and bottom of
your module and slide it out.
Wiring Y our Module
To wire the terminal block, you need:
• a small, flat-blade screwdriver
• Belden 8761 (shielded, twisted pair) cable or equivalent
CAUTION
POSSIBLE EQUIPMENT OPERATION
Before wiring your module, always disconnect power from
the SLC 500 system and from any other source to the
!
Before wiring the terminal block, take some time to plan your system:
• Ensure that the SLC 500 system is installed in a NEMA-rated
enclosure and that the SLC 500 system is properly grounded.
• Route the field wiring away from any other wiring and as far as
possible from sources of electrical noise, such as motors, transformers,
contactors, and ac devices. As a general rule, allow at lease 6 in.
(about 15.2 cm) of separation for every 120 V of power.
module.
Failure to observe this precaution can cause unintended
equipment operation and damage.
• Routing the field wiring in grounded conduit can reduce electrical
noise further .
• If the field wiring must cross ac or power cables, ensure that they
cross at right angles.
To wire your module, follow these steps:
1 Determine the length of cable you need to connect a channel to its
field device. Remember to include additional cable to route the drain
wire and foil shield to their ground points.
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