Current flow through a dry contact to DI Module

[RRoc]

How much current flows typically through a dry contact to a digital input module? Using 120VAC module and power.

I'm assuming around 30mA.

I'm wiring a Valves Open limit switch DI point and a Close limit switch DI point together on the common side.
I'm pretty sure I'm ok, but need some assurance that my .25Amp is sized correct. I see other designers jumper alot more and the plc panel function just fine.

 

[Mickey]

What the complete catalog number of your input module? The specification will usually give those numbers depending on the voltage applied.

 

[keithkyll]

30 mA is too high. I would use 12 mA.

AD Productivity and Click are ~11 mA. Siemens S7 is 7 mA. MicroLogix 1100 is 12 mA.

 

[Bit_Bucket_07]

How much current flows typically through a dry contact to a digital input module? Using 120VAC module and power.

I'm assuming around 30mA.

I'm wiring a Valves Open limit switch DI point and a Close limit switch DI point together on the common side.
I'm pretty sure I'm ok, but need some assurance that my .25Amp is sized correct. I see other designers jumper alot more and the plc panel function just fine.

You really only need to concern yourself with protecting the wiring for your input point. There is nothing to be gained by sizing your fuse to match the normal current draw of the input.