Remote I/O refresh problem

3 posts in this topic

Hi all,

I’m having some problems regarding a digital input from a remote ethernet coupler input.

My setup contais an Omron CJ2M cpu33, a switch, an Omron NS5 HMI (also ethernet) and 10 Wago Ethernet/IP couplers, all of which have 2 digital in- and 2 digital output cards.

Every machine cycle all couplers recieve an input from a regulair proximity switch, this signal is high for about half a second and switches at a frequency of about every 2 seconds.

Despite the fact there’s no high speed stuff going on here, the pulses are not processed properly. Monitoring my program I can see that the inputs are skipped and somtimes are not processed even for several machine cycles.

Is my network too slow, can it be a scan time issue, or something else.

I’ve come a long way building this system but I’m still fairly new to plc programming.

Hope someone has a suggestion.

Best regards,






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Are you sure it isn't just a monitoring issue with CX Programmer? The green contacts may not be indicating that actual status.

Try programming one of them to turn on an spare output so you can watch the LED on the output module.


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I’m sure. I set up a pulse check ladder, the main pulse (direct input to the Omron, so no problems there) has a two step counter which is reset every cycle by the pulses from the network nodes.

On very low machine speeds, all is fine, at higher speeds (still the sensors are set for half a second) these problems occur and my pulse counter runs to zero.

I could make the pulses longer by lengthening the cam which switches the proximity sensor, but I feel that doesn’t solve my problems.

Edited by andepand

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