PRODUCT INFORMATION
Product Overview
The Allen-Bradley 1771-IS is a specialized multiplexer input module designed for 1771 I/O chassis in PLC-5 systems. It occupies a single I/O slot. The module acquires 72 direct digital inputs. It can interface up to four 4-digit BCD thumbwheel switches. Alternatively, it accepts six 3-digit BCD thumbwheels or 72 discrete switches.
Internal circuitry supplies an input voltage of 5 VDC directly to connected input devices. The unit draws 0.8 A of current from the 1771 backplane. It provides conformal coating for environmental protection. Field connections terminate through a compatible wiring arm such as the 1771-WH or 1771-WF.
TECHNICAL DATA
Technical Specifications
| Parameter | Specification |
|---|
| Number of Inputs | 72 Direct Digital Inputs |
|---|
| Input Configurations | Four 4-digit BCD, six 3-digit BCD, or 72 discrete switches |
|---|
| Slot Requirement | 1 Slot |
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| Backplane Current Draw | 0.8 A |
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| Input Voltage Range | 5 VDC (module supplied) |
|---|
| Module Scan Time | 15.3 ms (normal), 5.1 ms (fast) |
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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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| Compatible Wiring Arm | 1771-WH or 1771-WF |
|---|
| Protective Coating | Conformal Coat |
|---|
| Mounting | 1771 I/O Chassis |
|---|
TECHNICAL INFORMATION
Features
- Supports 72 direct digital inputs across multiplexed circuits.
- Accepts four 4-digit or six 3-digit BCD thumbwheel switches.
- Supplies 5 VDC input loop power from internal module circuits.
- Features conformal coating to protect internal electronic assemblies.
- Provides selectable scan times of 15.3 ms normal and 5.1 ms fast.
TECHNICAL INFORMATION
Applications
- BCD thumbwheel switch data acquisition in PLC-5 automation systems.
- High-density discrete switch monitoring within 1771 I/O racks.
- Operator panel setpoint entry without consuming standard discrete input channels.
TECHNICAL INFORMATION
Connections / Interfaces
- Installs directly into any compatible 1771 I/O chassis slot.
- Field wiring connects via removable 1771-WH or 1771-WF wiring arms.
TECHNICAL INFORMATION
Installation Guidelines
- Align the module with chassis card guides before pressing firmly into the backplane.
- Secure the module locking latch to ensure stable mechanical seating.
- Pre-wire the 1771-WH or 1771-WF wiring arm before latching it onto the module frame.
TECHNICAL INFORMATION
Configuration Guidelines
- Configure module scan speed for either 15.3 ms normal or 5.1 ms fast operation.
- Map PLC-5 data table words to match the chosen multiplexing format.
TECHNICAL INFORMATION
Compatibility
- Compatible with Allen-Bradley 1771 I/O chassis and PLC-5 programmable controllers.
- Mates with 1771-WH and 1771-WF field wiring arms.
TECHNICAL INFORMATION
Lifecycle / Replacement Information
- The 1771-IS is a mature PLC-5 family hardware component.
- Units remain available through specialized automation surplus and refurbished hardware channels.
TECHNICAL RESOURCES
Documentation
COMPATIBILITY
Compatibility & Replacement
COMPATIBLE MODELSCompatible with Allen-Bradley 1771 I/O chassis and PLC-5 programmable 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 input devices connect to the Allen-Bradley 1771-IS?
The module interfaces up to four 4-digit BCD thumbwheels, six 3-digit BCD thumbwheels, or 72 discrete switches.
Does the 1771-IS require external input power?
No. The 1771-IS supplies the 5 VDC excitation voltage directly from internal module circuitry.
What is the backplane current draw of the 1771-IS?
The module draws 0.8 A from the 1771 chassis backplane.
What is the reference price for a refurbished 1771-IS module?
Observed market reference pricing is around $119.00 USD. This figure is an indicative reference price only, not a final quotation.
