PRODUCT INFORMATION
Product Overview
The Allen-Bradley 1771-ES is a PLC-5 Servo Encoder Feedback Expander Module designed for motion control. It interfaces incremental encoders directly to the chassis backplane. The module occupies two slots in a standard 1771 I/O chassis. It delivers a fast module update period of 2 milliseconds per axis. This unit handles closed-loop positioning feedback with high precision.
Engineered for industrial drive interfaces, the module supplies a +/- 10 Volt DC analog command output. It accepts 5 to 30 Volt DC incremental encoder signals. In addition, it integrates discrete auxiliary digital inputs for axis jog, stop-up, and override functions. A 1.7 Ampere backplane current draw supports internal signal processing and differential encoder reception.
TECHNICAL DATA
Technical Specifications
| Parameter | Specification |
|---|
| Category | PLCs |
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| Product Line | PLC 5 |
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| Weight | 1.94 lbs (0.88 kg) |
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| Module Type | Servo Encoder Feedback Expander Module |
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| Inputs | 5-30 Volt DC Incremental Encoder. Auxiliary Digital Inputs: Jog, Stop-Up, Override |
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| Max Input Frequency | 250 Kilohertz Differential Input |
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| Outputs | +/- 10 Volt DC Analog Command |
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| Slots | 2 Slots Per ES |
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| Module Update Period | 2 ms/axis |
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| Backplane Current | 1.7 Amperes |
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| Wiring Arm | 1771-WA |
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| Pulse Capture Time | 50-9.999 Microseconds |
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TECHNICAL INFORMATION
Features
- Receives differential incremental encoder inputs from 5 to 30 Volts DC
- Generates +/- 10 Volt DC analog velocity or position command outputs
- Supports input pulse rates up to 250 Kilohertz
- Features dedicated auxiliary digital inputs for jog, stop-up, and override commands
- Maintains a rapid 2 millisecond per axis loop update rate
- Provides pulse capture timing within 50 to 9.999 microseconds
TECHNICAL INFORMATION
Applications
- Closed-loop servo drive positioning within PLC-5 controller architectures
- Axis positioning feedback processing for industrial motion stages
- Encoder interface expansion across standard 1771 I/O chassis installations
TECHNICAL INFORMATION
Connections / Interfaces
- Differential encoder wiring connects via 1771-WA or 1771-WB field wiring arms
- Discrete auxiliary input terminals support stop-up, override, and jog interlocks
- Bipolar analog output connects to external servo drive command inputs
TECHNICAL INFORMATION
Installation Guidelines
- Insert the module into two adjacent slots of a 1771 I/O chassis
- Verify that the chassis power supply can source 1.7 Amperes at 5 Volts DC
- Seat the 1771-WA or 1771-WB field wiring arm securely onto the chassis pivot posts
- Use shielded twisted-pair cabling for all differential encoder and analog command signals
TECHNICAL INFORMATION
Configuration Guidelines
- Configure encoder pulse resolution and direction parameters through PLC-5 block transfer instructions
- Verify axis travel limits using the dedicated auxiliary digital input terminals
- Calibrate the +/- 10 Volt DC command scaling to match the servo amplifier input range
TECHNICAL INFORMATION
Compatibility
- Allen-Bradley 1771 I/O chassis assemblies
- Allen-Bradley PLC-5 processor platforms
- Allen-Bradley 1771-WA and 1771-WB wiring arms
TECHNICAL INFORMATION
Lifecycle / Replacement Information
- The 1771-ES is a legacy PLC-5 motion expansion module
- Maintenance replacement modules remain accessible through secondary surplus and refurbishment channels
TECHNICAL RESOURCES
Documentation
COMPATIBILITY
Compatibility & Replacement
COMPATIBLE MODELSAllen-Bradley 1771 I/O chassis assemblies Allen-Bradley PLC-5 processor platforms Allen-Bradley 1771-WA and 1771-WB 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
How many chassis slots does the 1771-ES require?
The module requires two adjacent slots in an Allen-Bradley 1771 I/O chassis.
What is the update rate for an axis controlled by the 1771-ES?
The module operates with a fast loop update rate of 2 milliseconds per axis.
Which field wiring arms are compatible with the 1771-ES?
The module uses standard Allen-Bradley 1771-WA or 1771-WB wiring arms for field terminations.
What is the reference price for a replacement 1771-ES module?
Observed market reference pricing is around $328.00 for used surplus units. This is indicative market reference pricing only and is not a final quotation.
