Relay Cards & Connectors
Interface relay cards and connector systems for clean, serviceable panel wiring.
About Relay Cards & Connectors
A relay card (or relay interface module) sits between a PLC and the field. PLC outputs are low-current transistor or relay contacts that should not switch contactor coils, solenoids or lamps directly, and field inputs can carry noise or wrong voltages back into the controller. A relay card switches the load through its own relay contacts, isolates the two circuits, and gives each channel an LED and a replaceable relay.
Microtech supplies Connectwell and Procom relay cards and connector systems. Connectwell's range includes the CIMRE fully enclosed relay interface modules in 2, 4 and 8 channel versions (expandable to 32 channels), CRM modular and CSR slim relays, and connector modules — D-Sub, IDC/FRC and RJ45 — that link pre-made cable harnesses from PLC I/O cards to screw or screwless terminals. Procom relay cards are available from 1 to 18 channels.
Using relay cards and pre-wired connector modules keeps the PLC wiring short and tidy and makes a failed channel a plug-in fix rather than a rewiring job. We use the same cards in our own panels.
Key specifications
| Relay card channels | Connectwell CIMRE 2 / 4 / 8 channel (expandable to 32); Procom 1 to 18 channel |
|---|---|
| Contact configuration (Connectwell CIMRE) | 1 CO (changeover) per channel |
| Relay types | Electromechanical and solid-state relays (Connectwell CSR slim range) |
| Enclosure (Connectwell CIMRE / CRM / CSR) | IP20, fully enclosed on CIMRE |
| D-Sub connector modules | 9 to 50 pin, male / female, up to 3 A per pin |
| IDC / FRC connector modules | 10 to 64 pin, up to 2 A per pin |
| Other modules | RJ45 interface modules; diode protection and lamp-test modules |
| Indication | LED status per channel |
Features & benefits
- Electrical isolation between the PLC and field devices
- Pluggable relays for quick replacement of a failed channel
- LED indication on every channel for fault finding
- Slim relay modules that save panel width
- Pre-wired connector modules that cut PLC wiring time
- Custom relay interface boards from Connectwell (IMRE series) for special requirements
Where it’s used
- PLC and DCS marshalling panels
- Machine control panels
- AMF, ATS and generator control panels
- Process plant and refinery control rooms
- Building and infrastructure automation
Standards & compliance
Relay Cards & Connectors — FAQs
Why use a relay card instead of wiring directly to the PLC?
The relay card protects the PLC from field-side faults and voltage mismatches, lets the PLC switch loads it could not handle directly, and turns a failed output into a quick relay swap instead of a damaged I/O card.
What is the difference between a relay card and a connector module?
A relay card switches and isolates signals through relays. A connector module (D-Sub, IDC/FRC or RJ45) simply breaks out a pre-made PLC cable to individual terminals, with no switching, to speed up and tidy the wiring.
Can you supply relay cards to match a specific PLC?
Yes. Tell us the PLC make and I/O card, the coil voltage and the load each channel must switch, and we will select the relay card, connector module and cable to suit.
