Diamond Systems IR104-PBF High Density Optoisolated Input + Relay Output PC/104 Module

Control panels that monitor and drive dozens of field points need isolation on every channel and wiring that can be changed without a soldering iron. The IR104-PBF from Diamond Systems is a high-density PC/104 digital I/O module for industrial applications that need isolation between the computer and the external signals it monitors and controls, with 20 optoisolated inputs and 20 relay outputs on one board.

Each of the 20 optoisolated inputs accepts AC or DC signals from as low as 3 V to as high as 24 V, with 2.8k input impedance, so the same board can read low-voltage logic as well as 12 V and 24 V control circuits. The inputs sit on a 40-pin header at the top of the board that mates with standard ribbon cable, such as Diamond’s C-40-18.

The 20 relay outputs are SPST Form A with normally open contacts and switch both AC and DC loads, up to 5 A at 30 V DC or 250 V AC, with maximum ratings of 150 V DC, 150 W and 1250 VA, and a UL rating of 5 A at 30 V DC or 250 V AC. Contact resistance starts at 30 mΩ, operate time is 6 ms and release 3 ms, and relays are rated for 20,000,000 mechanical cycles or 100,000 at full power. Contacts land on two detachable screw terminal blocks of ten relays each, taking 14 to 28 AWG wire. The OPMM-1616-XT offers 16 inputs with changeover relays across -40 to 85 °C, and the PMM-P is a relay-only board.

The IR104-PBF runs on +5 V at 110 mA typical with all relays off and operates from -25 to 70 °C. Its tallest components exceed the PC/104 height limit, so Diamond advises mounting it at the top of the stack when the board above has bottom-side parts. It suits PC/104 hosts such as the ATHENA IV SBCs, and Diamond quotes an MTBF of 57,450 hours.