The Allen-Bradley 1771-WC, also cataloged as the 1771-WC Wiring Arm, operates as a dedicated hardware component for TTL and low-current signal termination within Allen-Bradley PLC-5 control systems.
Hardware Specifications
Parameter
Specification
Model
1771-WC
Brand
Allen-Bradley
Origin
USA
Weight
0.25 lbs (0.11 kg)
Dimensions
4.5 x 12.4 x 6.3 inches
Operating Temp
0 to 60 deg C (32 to 140 deg F)
Power Consumption
Passive Component (0 W)
Module Type
Wiring Arm
Application
TTL, Low Current Signals
Max Number of I/O
8 I/O Points
Number of Terminals
10 Terminals
Contact Plating
Gold Plated
Screw Torque
7 to 9 lb-in
Conformal Coating
Yes
Required External Power
None
Typical AC Signal Delay (Off)
29 (+/- 8) ms
Typical DC Signal Delay (Off)
30 (+/- 7) ms
Backplane Bus & I/O Isolation Execution
The 1771-WC facilitates direct electrical connection between 1771 series TTL/low-current I/O modules and field devices, utilizing gold-plated contacts to prevent terminal degradation and maintain low-resistance signal paths. Its conformal coating provides environmental protection against atmospheric moisture and contaminants, ensuring signal integrity across high-density I/O configurations connected to the PLC-5 backplane bus.
Frequently Asked Questions
Q: Does the 1771-WC wiring arm require an external supply voltage or backplane power?
A: No, the 1771-WC is a passive mechanical swing arm requiring no external power supply or current from the 1771 backplane bus.
Q: What wire termination styles are supported by the 1771-WC terminal connections?
A: Conductors up to AWG 14 can be connected either via direct wire clamping or using spade lugs attached to the terminal screws.
Field Installation Guidelines
Chassis Alignment: Align the hinge slots at the base of the 1771-WC wiring arm with the lower pivot bar on the designated 1771 I/O chassis slot.
Terminal Wiring: Fasten field conductors (up to AWG 14) or spade lugs under the 10 screw terminals, applying a torque of 7 to 9 lb-in to prevent over-tightening or loose contacts.
Module Interlocking: Pivot the arm upward into the face of the installed I/O module until the top latch engages firmly, securing the gold-plated contacts.
Shielding & Grounding: Route low-voltage TTL signal drain wires to a low-impedance ground bus bar inside the panel to prevent noise pickup.
Strain Relief: Fasten the incoming wire bundle to the integrated cable tie slot on the bottom of the arm to prevent mechanical tension on individual screw terminals.
