PRODUCT INFORMATION
Product Overview
The Allen-Bradley 1771-ISC is a single-slot Input Multiplexer Module designed for 1771 rack-based PLC-5 systems. It provides multiplexed signal acquisition for up to 72 direct digital inputs. The internal hardware supplies a 5V DC input voltage directly to connected switch contacts. It supports four 4-digit BCD thumbwheels, six 3-digit BCD thumbwheels, or 72 discrete switches.
The module occupies one slot in a standard 1771 I/O chassis. It requires a backplane current draw of 0.8 amperes at 5V DC. Operating scan times measure 15.3 milliseconds in normal mode and 5.1 milliseconds in fast mode. Field wiring connects using compatible wiring arms such as the 1771-WH or 1771-WF. Configuration switches on the module select operating modes and signal timing.
TECHNICAL DATA
Technical Specifications
| Parameter | Specification |
|---|
| Backplane Current | 0.8 Amperes |
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| Category | PLCs |
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| Input Voltage Range | 5 Volts DC (Supplied by Module) |
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| Model Status | Earlier Model |
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| Module Scan Time | 15.3 ms (normal) and 5.1 ms (fast) |
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| Module Type | Specialized I/O Module |
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| Number of Inputs | 72 Direct Digital Inputs for up to four 4-digit BDC TW, six 3-digit BDC TW, or 72 discrete switches |
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| Product Line | PLC 5 |
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| Slots | 1 Slot |
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| Typical AC Signal Delay (Off) | 45 (+/- 15) ms |
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| Typical DC Signal Delay (Off) | 50 ms |
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| Weight | 1.00 lbs (0.45 kg) |
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| Wiring Arm | 1771-WH |
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TECHNICAL INFORMATION
Features
- Accepts up to 72 direct digital inputs from switches or thumbwheels.
- Supplies 5V DC input excitation directly from the module.
- Supports selectable scan rates of 15.3 ms normal and 5.1 ms fast.
- Installs directly into a single 1771 I/O chassis slot.
- Uses removable wiring arms 1771-WH or 1771-WF for field termination.
TECHNICAL INFORMATION
Applications
- Interfacing multi-digit BCD thumbwheel switches in PLC-5 architectures.
- Multiplexing high-density discrete operator panel switch arrays into single rack slots.
- Data acquisition from digital pushbuttons and selector switches.
TECHNICAL INFORMATION
Connections / Interfaces
- Connects to field devices via 1771-WH or 1771-WF wiring arms.
- Backplane interface plugs directly into 1771 series rack backplanes.
TECHNICAL INFORMATION
Installation Guidelines
- Insert the module into any available slot in a 1771 I/O chassis.
- Ensure chassis power is switched off before inserting or removing the unit.
- Tighten wiring arm screws securely to preserve signal integrity.
TECHNICAL INFORMATION
Configuration Guidelines
- Set the on-board switches to select between normal and fast scan modes.
- Configure the multiplexer addressing to match connected thumbwheels or discrete contacts.
TECHNICAL INFORMATION
Compatibility
- Compatible with Allen-Bradley 1771 I/O chassis and PLC-5 controllers.
- Mates with 1771-WH and 1771-WF field wiring arms.
TECHNICAL RESOURCES
Documentation
COMPATIBILITY
Compatibility & Replacement
COMPATIBLE MODELSCompatible with Allen-Bradley 1771 I/O chassis and PLC-5 controllers. Mates with 1771-WH and 1771-WF field wiring arms.
Verify compatibility against the exact Part Number, revision and manufacturer documentation before ordering.
PART VERIFICATION
Before You Order
Industrial automation parts can share similar model names, suffixes and revisions. Confirm the complete manufacturer Part Number before purchase.
01Check Part NumberMatch the complete ordering code on the existing unit.
02Confirm RevisionCheck suffix, hardware or firmware when applicable.
03Send a Label PhotoWe can review a clear label photo when identification is uncertain.
ORDERING PROCESS
From RFQ to Dispatch
1Submit Part Number2Verify Product Identity3Confirm Stock & Condition4Issue Quotation5Dispatch & Tracking
PRODUCT FAQ
Frequently Asked Questions
What is the primary function of the Allen-Bradley 1771-ISC?
The 1771-ISC multiplexes up to 72 direct digital inputs into a PLC-5 control system.
What are the scan time specifications for the 1771-ISC module?
Scan time is 15.3 milliseconds in normal mode and 5.1 milliseconds in fast mode.
Which wiring arm is required for the 1771-ISC?
Field connections utilize the 1771-WH or 1771-WF wiring arms.
What is the reference price for a replacement 1771-ISC module?
Observed market reference pricing is approximately $329 USD for used or refurbished units. This figure represents indicative market reference pricing only and is not a final quotation.
