Mitsubishi register going to 0 on power outage

PFrog · Feb 4, 2014

Hello,

Just getting a little familiar with Mitsubishi ladder logic and it throws me another curveball. I have a GOT 1600 panel tied to an A series (Mitsi) PLC. I added ladder logic to create cycle counters that are displayed by the GOT. The problem being is that it appears when power is cycled to the GOT it zero's out the PLC register... not cool. I'm looking around for some type of startup configuration but have not seen any yet. Any ideas?

Thanks

PFrog · Feb 4, 2014

PLC Logic is written as:
(Conditions that trigger the counter) [DINCP D104]

I

dploof23 · Feb 4, 2014

PFrog said:
PLC Logic is written as:
(Conditions that trigger the counter) [DINCP D104]

I

You need to check the PLC parameters and assign which data registers you want to be battery backed.
On the project tree select PLC parameters and go to the device tab. You can define this there.

Regards,

Dave

PFrog · Feb 4, 2014

I take it that it is the latch start and end that I would have to adjust. Just wanted to verify that is what has battery backup. Currently the points are 110 thru 248. so I would just have to make sure my values fall within that or change the window (they are currently D104 and D106). If I do change the window I don't have to worry about any additional configuration, correct? Just change the window and write it to the PLC?

Seems a little weird that cycling power on the GOT would cause an issue with the PLC?

BobB · Feb 4, 2014

Probably recycling power on the GOT writes 0 to the registers. That is what I would suspect.

Bit_Bucket_07 · Feb 4, 2014

BobB said:
Probably recycling power on the GOT writes 0 to the registers. That is what I would suspect.

I agree, that is what it sounds like. I'm not familiar with a "GOT", but I would look for a memory retentive option for the tag that is addressed to the PLC register(s) that is/are being cleared.

dploof23 · Feb 4, 2014

PFrog said:
I take it that it is the latch start and end that I would have to adjust. Just wanted to verify that is what has battery backup. Currently the points are 110 thru 248. so I would just have to make sure my values fall within that or change the window (they are currently D104 and D106). If I do change the window I don't have to worry about any additional configuration, correct? Just change the window and write it to the PLC?

Seems a little weird that cycling power on the GOT would cause an issue with the PLC?

Yes the latch start and latch end is what you are after....just change the setting to include the registers you want and write. No other configuration would be necessary but make sure all the registers you include would be ok to retain their value at power cycle.

As far as just power cycling the GOT and losing the values...that doesn't make sense to me. I don't think that should do anything to the data in the PLC. I will confirm this tomorrow.

Dave

PFrog · Feb 5, 2014

[/ATTACH]

I've attached screen shots of the code. I am sending a reset from the GOT if the momentary button is pressed for 5 seconds...

dploof23 · Feb 5, 2014

PFrog said:
[/ATTACH]

I've attached screen shots of the code. I am sending a reset from the GOT if the momentary button is pressed for 5 seconds...

It still does not make sense that your count would reset on a power cycle of only the GOT, regardless if the data register is battery backed or not. You can monitor online the piece of code you posted and power cycle the GOT to watch what happens.

Dave

Goody · Feb 5, 2014

It would appear from the code you have showed us that the registers D104 and D106 are 32 bit.
You are using 16 bit MOV K0 to these registers (instead of DMOV)

I don't think this is your problem, more of a point of good programming.

I know of no instance where rebooting a GOT HMI would cause it to clear registers in the PLC - but then again I have only worked on a few GOT's. Maybe a start up file does this, I don't know

dploof23 · Feb 5, 2014

Goody said:
It would appear from the code you have showed us that the registers D104 and D106 are 32 bit.
You are using 16 bit MOV K0 to these registers (instead of DMOV)

I don't think this is your problem, more of a point of good programming.

I know of no instance where rebooting a GOT HMI would cause it to clear registers in the PLC - but then again I have only worked on a few GOT's. Maybe a start up file does this, I don't know

There is no startup file to do this that I have ever encountered and I have roughly 15-20 GOT's here I have used for various projects.

Dave

PFrog · Feb 5, 2014

I changed the registers to being latched (fixed the code issue with a DMOV) and everything works properly.

I noticed that when I cycled power to the GOT I lost comm to the PLC with my PC running GX. Not sure why since I was plugged into the PLC. It is an A series so maybe the age has something to do with it. I would imagine this is what allowed the registers to reset when not latched? A momentary PLC hiccup when resetting GOT?

Goody · Feb 5, 2014

It would seem that you think you are only power cycling the HMI but in reality you are pulling the plug on both. Sometimes the plc's take a while for the lights to go off after power is disconnected - so you think it's still on.

This coupled with the fact that you lost communication during power down of the HMI and now the registers are battery backed and keeping their data all points to both losing power at the same time.

It's an assumption I know but all the same - glad we got it cleared up

PFrog · Feb 5, 2014

I'm only cycling power on the HMI, in this scenario, because I am doing an I/O check on it (or anything else) that requires it to do a reboot. The PLC power never drops... I am also glad to be done with it! Thanks for the help everyone!

Mitsubishi register going to 0 on power outage

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