Omron hmmmm

arkyny · Apr 22, 2013

Anybody have experience with the Omron CJ1M-CPU2 PLC? I received a machine last week with this processor/PLC and at present acquiring the programming software. While I have run the machine without any (brain) diagnostics at the present, I am finding that it is unpredictable,eg, LVDT readings. Using Solartron LVDT sensors, on a known surface, I get different results almost after every run. The signal runs through an analog input module, then display to HMI. The device that it measures is smooth and controlled by a stepper motor that takes a snapshot every half resolution x 3. ?

BobB · Apr 23, 2013

It is probably a CJ1M-CPU12.
You will require a special cable whether it be for the peripheral port of a serial port.
I would not expect the PLC analogue input to play up - more likely the device, incorrect wiring, noise.
If there are several loop powered devices wired into the same analogue input card signal isolators are required.
If the analogue input is 1-5V, 0-10V or -10/+10V I would suggest you may have to have a look and see if there is any induction into the wiring - 4-20ma is much more immune to noise.

mendonsy · Apr 23, 2013

You will need CX Programmer and a CS1W-CN226 cable to talk to a CJ1M PLC. There is no CJ1M-CPU2 so its either a CPU12 or a CPU21, 22, or 23.
Don't jump to the conclusion that there is anything wrong with the PLC or programming, although that is certainly a possibility. Your repeatability problem could be a poorly designed machine, or your parts could be a whole lot worse than you think they are.
I have seen more than one case where the surface finish on a part was outside the part tolerance range making it impossible to get repeatable readings.

Omron hmmmm

arkyny

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