PLCs & Industrial Computing

PLC parts are identified by exact catalog number, and a small difference in the suffix or revision letters can change what a module will work with.

Modules must match the platform

A CPU, I/O module or power supply has to suit the chassis or backplane generation it plugs into, so identify the platform first (which controller family and rack style), then the module. Catalog numbers also carry series or revision letters, and firmware levels can decide compatibility with the rest of the system.

I/O details that cause wrong orders

For discrete I/O check the voltage (24 V DC, 120 V AC or 240 V AC), whether inputs and outputs are sinking or sourcing, and the point count. For analog I/O check the signal range, such as 4-20 mA or 0-10 V, and the resolution. HMIs and industrial PCs add screen size, resolution and the software version the project was built in.

Controllers past their active life

Many controller families are past the manufacturer active life. A listing may be new, new old stock or refurbished, and that changes the firmware level, the remaining service life and what you can expect from the part, so say which condition you can accept when you ask for a quote. We state the condition on every quote.

What to have ready

• The complete catalog number, including series and revision letters
• Firmware revision, if known
• The platform and the slot or rack position
• Voltage and I/O type (discrete or analog, sinking or sourcing)
• Which condition is acceptable: new only, or surplus and refurbished as well

Related guides and tools

• Tool: 4-20 mA Calculator
• Guide: Obsolete Allen-Bradley Parts
• Guide: Obsolete GE Fanuc / Emerson PLC
• Tool: GE Fanuc IC Lookup
• Tool: Obsolete Part Lookup

Not sure which one you have? Send us the number, a nameplate photo or the dimensions and the order desk replies within 1 business day.