Sign in to follow this  
Followers 0
presario2100

Forcing PLC I/O

6 posts in this topic

Hi guys: I'm using GPPW SW4D5-GPPW-E Ver4.0 to programming the PLC, I have question need to ask, how to forcing the PLC I/O. I tried use "Device test" section to force the I/O, but it's not working. Did any Mitsubishi FX series expert here know why ? Please, really need your help.

Share this post


Link to post
Share on other sites
Mitsubishi P.L.C.s are not the same as some other P.L.C.s that is to say if you force I/O they are forced on and remain on until they are reset or forced off. Mitsubishi P.L.C.s will only force on for one scan of the P.L.C. if there is nothing in the program to keep the output on. The input will only be on for the single scan because the input is off else why would you force it on in the first place. Rodney

Share this post


Link to post
Share on other sites
It is also depending on the used system, FXxN, A-series or System Q. An output is only for one single scan and a input can be overruled. That means the input remains high untill it is forced low again. (even a reset of the PLC is not helping)

Share this post


Link to post
Share on other sites
You can happily force outputs ON as long as the PLC is not in the RUN position. I often do this to test the wiring prior to running the programme. Failing that, as others have said, you can include, if you want to, an extra M coil in parallel with the normal code that drives the output. This M coil will not be referenced by the programme, only by the programming software (or HMI if you want a "manual" facility).

Share this post


Link to post
Share on other sites
as you already know by now, forcing in Mitsubishi means SET and that's fine unless program is running and there is logic that can change state of that emory location. be careful when forcing inputs, they behave a bit different. if actual input is low, you can force it high but not the other way around. also if you force input high, it stays high even if actual input changes. it is not bad idea to restart plc after testing, just to make sure all input forces are reset.

Share this post


Link to post
Share on other sites
Please try not to start new topic, when one is already there. It makes it easier to offer help. The only "forces" in GPPW are ones you tried already. (Device Test, Force...) If your program is running, you can stop PLC first and then use this feature.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0