FX1N-60MT - something is wrong

[pszczepan 2]

Hi ! Everything worked until yesterday. Terminal shows message "Systemfel Corrupt Block 250" When I made PLC diagnostic I got error 6706 in step 879. I did something and now there is "No Errors" but "Corrupt block 250" on terminal still in force I am not really familar wth GX Developer, but I think that something is wrong with CPU. As you see: I have monitor mode and I try to Force On M562 to check if instruction DDIV works ( value in D472 should be changed - D472 is only in this step), but nothing is happening when I try to force the Input On Value in D472 is also really strange. Maybe you could give me any clue to find out what is going on with this PLC and what the E-terminal message can mean. Thanks Pawel

[Paul Ked 0]

The error message you are getting is most likely in the HMI not the PLC. Check Block 250 and re-load the program into the HMI. Regards Paul Ked

[pszczepan 2]

OK - I will find out what cable and soft I need to connect to E-Terminal. I use mostly Omron and force on works, but now with this FX1N it does not work. Why I cannot force on input M562 - maybe there is some other way. Pawel

[Paul Ked 0]

It is probably being turned off somewhere else in the program. Search for the outpupt coil and you should see this. Regards Paul Ked

[pszczepan 2]

In Omron FORCE ON works with the highest priority. IF you want to Force On the internal input you can do that whenever you want - doesnot matter if the PLC program turn on/off this input. Melsec does not work this way? I tried also to change value D472 using also Device Test (word device) but nothing change with the value which is beneath D472 in ladder view ( see picture in first post) - is it normal? It is completely strange if I compare it to Cx-designer for Omron. hmm thanks Pawel

[Crossbow 296]

Force in Mitsubishi FX does not override physical input signals or outputs set in PLC program. Q Series supports forced I/O which override PLC and input, but only for physical I/O (X and Y) not for M bits.

[pszczepan 2]

Wow - what's a pity So - How I can switch on step 879 (from the GX Developer) to check how the instruction DDIV works - I mean what value will be in D472 after it. How I can set different value in D472 - This minus is strange for me. This values goes to timer and if it is negative it can give error. When I look into Device Memory a lot of D addresses have negative values - hmm Pawel

[Goody 5]

If you want to force that line to become true (to see the result of the ddiv) you can use an unused internal bit, Find the list of used devices - type in M for m bits and go down until you find an unused bit. Put that in parallel with the bit you tried to force and force the new bit instead. and by the way, in mitsi you will need to unforce afterwards too.

[pszczepan 2]

Ok - I will do that this way and what about overwrite D472 value. I cannot do that using Device test - even I write f.e. 4 DEC to D472 in Device test still I have negative value in line 879. At this moment Line is not active - DDIV instruction is not executed. thanks Pawel P.S. I didnot know that GX-Developer and/or Melsec is not functional and user friendly

[speakerman 4]

Hey Pawel; One of the different things about the Mitsu PLC is the way it handles its registers. It takes some getting used to, and then it gets easier. They don't look right unless they are contantly computed, especially the doubles. First, I would recommend that you make sure your registers are spaced at least four apart wherever you are doing DDIV, or DMUL, or any double register function. Next, I would recommend re-writing the rungs with math functions to be driven by M8000, or whatever internal PLC bit for your CPU is the 'run' monitor, and always on. Then move the bit that you want to drive the timer with down onto the branch the timer is on. This would keep the register constantly updating, so you could see it, and still only drive the timer when you want based on the code example. See the attached pic for a simple representation of that. Hope this helps, speakerman.