Rockwell hmi coms issues

[stu]

Hi
I have a couple of hmi panel view plus 700
Hmi and we keep dropping coms /stars in the data boxes
I’ve checked the plc and unmanaged switch and can’t see an issue , if we reboot the power then it starts ok ?
Is there any way I can capture this fault?

 

[mike3475]

is the PLC and all HMIs at the same subnet and connecting to one unmanaged switch? if that is the case, i would replace unmanaged switch to try.

 

[stu]

No this is on 2 separate machines
Thanks

 

[James Mcquade]

It may be that your data boxes are not big enough for the data.
if it is an integer or real number, is the data box on the panelview set up for a negative number?
is the data box set up for a larger number than you thought possible?
james

 

[stu]

Thanks for the reply’s.
This is only a intermittent issue it does normally work ok until the we have a drop of communication
And the only way I can get it to reboot is turning the power off and on ?
Don’t know how to capture the cause of this issue

 

[dummy_bit]

Check the comm settings of the HMIs and the PLCs. If they don't match or are not set to auto-negotiate, it may cause some connectivity but tends to be flakey. I had this issue with a PLC where it would stop communicating after so much time elapsed due to mis-matched settings. We'd have to power cycle the machine then it would start working again. Check the communication section of your PLC for FCS errors or packet collisions.

 

[Operaghost]

If you are seeing question marks, then it is a loss of communications. If you are seeing asterisks (stars) that means the data is too large to be displayed. For example the object is formatted for two characters but the number is 100 or larger. That would require three characters, so it would be too large to be displayed. You would then see two asterisks ** instead of a value. If you had lost communications you would see two question marks ??

OG