Allen-Bradley 175-OW16I Relay Isolation Output Module

The Allen-Bradley 1756-OW16I is a ControlLogix 16-point isolated relay output module that provides 16 independently isolated normally-open contacts in a 36-pin backplane interface, designed to separate field loads from the controller logic. Each channel can switch loads up to 1 A at 5–30 V DC, 0.5 A at 48 V DC, 0.22 A at 125 V DC, or up to 1.5 A at 120 V AC (50/60 Hz) and 0.75 A at 240 V AC (50/60 Hz); the operating voltage range is 5–125 V DC or 10–240 V AC, with pilot duty rated at C300/R150. The module is built with 250 V continuous isolation between outputs, backplane, and output-to-output, and it draws about 150 mA from the backplane at either 5 V or 24 V supplies, contributing to a total backplane power of 4.4 W. Switching delays are a maximum of 10 ms for both Off-to-On and On-to-Off transitions, with an initial contact resistance up to 100 mΩ and an off-state leakage of up to 1.5 mA per point. Rated life reaches up to 300,000 cycles resistive and 100,000 cycles inductive, with a maximum switching frequency of about 1 operation per 3 seconds. Outputs are scheduled and synchronized within 16.7 s of Coordinated System Time, and each channel remains galvanically isolated from the backplane to protect the logic from field voltages. Field wiring is via removable terminal blocks (1756-TBCH or 1756-TBS6H). Common Raleigh-ready applications include driving relays, contactors, or other loads that require galvanic isolation in a ControlLogix I/O network, making the 1756-OW16I a robust choice for safely interfacing high-power field devices with a PLC.