rslogix bit not read from panelview

tlona · Oct 27, 2010

I have a panelview plus 1000 that is directing commands to micrologix 1500 thorught the RSlogix 500 software. The system has been ion operation for more than two years and working fine. I have two bits (b3:50/1 & b3:50/5) that are enabled by momentary pushbuttons from the panelview. For some reason now these bits are not being the enable command from the panelview. I have numerouse other bits that are being set from paenlview so I do not believe this is a comm problem. Any ideas?

gscure · Oct 27, 2010

Overwriting

Has the code been changed at all recently?

My idea is that maybe the code was changed so that these bits are being overwritten by logic inside the PLC. This could be either by OTE or by the word level.

Just an idea.

tlona · Oct 27, 2010

no. I checked that, the TAG in the RS Studio is the same as that in the RSlogix. Could this be a power issue maybe where there was a spike or dip. The Microlox and Panelviel are both fed from a 24Vdc ps which I think would filter any of that out.

Bob O · Oct 27, 2010

Long shot but have you tried to reboot both PV+ and ML.

tlona · Oct 27, 2010

yes, i just did that and all is back to "normal" but how did it get in that state to begin with? I seems all of the bits that were not working were all realted to one subroutine. My fear is that I leave the jobsite and it happens again. I hate when things fix themselves.

Mickey · Oct 27, 2010

tlona said:
yes, i just did that and all is back to "normal" but how did it get in that state to begin with? I seems all of the bits that were not working were all realted to one subroutine. My fear is that I leave the jobsite and it happens again. I hate when things fix themselves.

Is this subroutine conditional? Post your .RSS file ( zip it first) and maybe someone can spot something.

OZEE · Oct 27, 2010

I've seen panelview momentary bits "hang". They set, but don't reset.

My solution has been to make them latching. Then unlatch the bit in the PLC at the end of the program scan. So far, this hasn't failed me. (Hope that didn't just jinx it...)

harryting · Oct 27, 2010

I remember having issue with scan time & momentary buttons in Fix32 a long time ago. Now i just follow OZEE's way of setting the bit in HMI then reset them in PLC.

tlona · Oct 27, 2010

The subroutine is not conditional. This system has been in operation for more than two 1st and this is the first case. I will try the suggestions listed here. Thanx for all of the input

shoelesscraig · Oct 27, 2010

OZEE said:
I've seen panelview momentary bits "hang". They set, but don't reset.

My solution has been to make them latching. Then unlatch the bit in the PLC at the end of the program scan. So far, this hasn't failed me. (Hope that didn't just jinx it...)

I never thought of doing that! Nice idea!

lostcontrol · Oct 28, 2010

shoelesscraig said:
I never thought of doing that! Nice idea!

Unlatching bits at the end of the scan used to be/is quite common, to overcome slow serial comms type issues. Basically, it overcomes the particular HMI in use method of doing a momentary operation.
I have seen some that you can configure the time the bit is held hi, & others that just have a set function.

rslogix bit not read from panelview

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