1771-WS Allen-Bradley Weigh Scale Module

1771-WS Allen-Bradley Weigh Scale Module | New & Original Stock

Availability: 20 left in stock

Allen-Bradley 1771-WS PLC-5 Weigh Scale Module The Allen-Bradley 1771-WS, also cataloged as the 1771-WS Weigh Scale Module, operates as a...

SKU: 1771-WS

Manufacturer: Allen Bradley
Product No.: 1771-WS
Product Type: Weigh Scale Input Modules
Product Origin: USA
Payment:T/T, Western Union
Weight: 570g
Shipping port: Xiamen
Warranty: 12 months

Description Reviews

Allen-Bradley 1771-WS PLC-5 Weigh Scale Module

The Allen-Bradley 1771-WS, also cataloged as the 1771-WS Weigh Scale Module, operates as a dedicated hardware component for converting load cell signals into accurate digital weight data within PLC-5 I/O chassis platforms.

Hardware Specifications

Parameter	Specification
Model	1771-WS
Brand	Allen-Bradley
Origin	United States
Module Type	Weigh Scale Input Module
Input Channels	1 channel
Load Cell Compatibility	Up to 4 x 350 ohm full Wheatstone bridge load cells
Excitation Voltage	10 VDC
Input Signal Range	0 to 30 mV
Resolution	16-bit
Backplane Current	1.5 A
Input Power	5 VDC
Power Consumption	1.2 W
Isolation Voltage	1500 VAC for 1 minute
Common Mode Rejection	100 dB
Compatible I/O Chassis	1771-A1B, 1771-A2B, 1771-A3B, 1771-A3B1, 1771-A4B, 1771-AM1, 1771-AM2
Operating Temp	0 to 60 deg C
Storage Temp	-40 to 85 deg C
Humidity	5 to 95% non-condensing
Dimensions	178 x 50 x 180 mm
Weight	0.57 kg (1.25 lbs)

Backplane Bus Communication Velocity and Density Scaling

The 1771-WS leverages the native Allen-Bradley 1771 backplane bus communication velocity to execute deterministic block transfer reads (BTR) and block transfer writes (BTW) directly interfacing with the PLC-5 processor. This localized processing model ensures high-speed I/O density scaling by offloading the complex 16-bit analog-to-digital weight calculation parameters from the primary CPU. Firmware flash compatibility restrictions apply based on the series revision, maintaining stable communication profiles across legacy 1771 universal I/O chassis architectures without degrading backplane network bandwidth.

Frequently Asked Questions

Q: What is the maximum number of load cells that can be driven by a single 1771-WS module?

A: The internal excitation power supply of the module delivers 10 VDC and is rated to drive up to four parallel 350 ohm full Wheatstone bridge load cells simultaneously.

Q: Does the 1771-WS support hot-swapping while the 1771 I/O chassis backplane is energized?

A: No. The 1771 architecture requires the chassis power supply to be fully de-energized prior to inserting or removing the module to prevent transient electrical damage or disruption to backplane communications.

Q: How is calibration data retained if backplane power is lost?

A: Calibration parameters, including zero and span targets, are transmitted via block transfer writes from the PLC-5 processor logic and stored in non-volatile memory or managed directly via the controller application code upon system initialization.

Field Installation Guidelines

Chassis Alignment and Keying: Ensure the plastic keying bands on the 1771 chassis backplane connector match the designated slot positioning for the 1771-WS module to prevent incorrect hardware insertion.
Shielding and Grounding: Terminate all load cell cable shields at a single, clean instrumentation ground point. Do not ground the shield at both ends to prevent the formation of ground loops that inject electrical noise into the 0 to 30 mV analog signal line.
Wiring Separation: Route low-voltage load cell signal wiring through dedicated conduit paths separated from high-voltage AC power lines or variable frequency drive (VFD) motor cables by a minimum distance of 300 mm.
Terminal Block Engagement: Verify that the field wiring arm is fully seated and securely latched onto the module frame prior to system power-up.

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