Dear All
If you are experience or had facing this issue the same . Please kindly share solution to solve this issue
We are using PLC of Honeywell with the model Control Edge HC900, it was installed 10 years ago. Recently, we are facing big issue on the paper machine as CPU auto reset and start within 3s and happened with high frequency ( 5 times/day ).We tried to execute many step to separate this system , but it is still happening with more high frequency . Till now I don't know what we will do to solve this issue
Our solution was executed . We have 4 cracks
1. Change new CPU
2. Change new crack for CPU
3. Replace and move AI/AO module on the crack of CPU to other crack
4. Separated some signal such as AI/AO
Note :
Even through we taken all module and just CPU HC900 C70 on this crack . The problem still happened .
Do you think this problem cause by noise from grounding
- We measure current with the cable of the grounding for all cable to connect with the controller such as DI,DO, AI,AO is 1.7 A. With this value whether impact to reboot the CPU of HC900 or not ? How much limited leakage current for this HC900 C70 ?

Thanks

 

The back-up lithium battery in a holder in the CPU holds operating variables (not the main program, but operating variables). At ten years of age, it is likely to be dead. I'd start by replacing the back-up lithium battery.

My experience shows that about 1/2 of all problems are power supply problems. Poor quality line power will cause a weak power supply to drop out momentarily. A desktop PC back-up uninterruptible power supply is not very expensive but can assure continuous AC power to the units DC power supply. It isn't clear whether you have tried a 2nd power supply, but that would be a suggestion also.

 

Dear Mr David
Thank you so much for your advice . This issue was solved by the noise from power supply . We replace new UPS with the other mode which have active and inactive filter . And we separated the ground cable between drive system and control system to terminate the noise on the CPU unit .

Thanks

Huu Phu