PLC losing parameters

[Bradford0662]

Good Morning All,

I have a Siemens 6ES5 466 PLC. We are intermittently losing parameters . We can pull the backup battery and power down. When it restarts, it loads from eeprom and runs fine for a while then all the parameters go to 0. Any help would be much appreciated.

 

[JesperMP]

6ES5 466 is an analog input card in an S5-115U rack, or an S5-135U rack or an S5-155U rack.

Suspects:
Electrical noise.
Brown-outs.
Defective CPU.
Defective rack.
Defective rack power supply.
Maybe combined with battery is low.

No matter if the PLC is an S5-115U, or an S5-135U or an S5-155U, it is totally obsolete, spare parts are difficult to get and are expensive.
A modern PLC will also have better diagnostics so you might get useful information to narrow down the error.
So........... time to bite the bullet.

 

[Nova5]

So you can write your way around this most likely until you can catch and nail the problem down.

use a Equal block, if the operational value is equal to zero(if its not supposed to be) then then a move block to mov a fixed value to that operational value.

Of course this can also lead to complacency and you forgot about it,, then boom.