Johnny T
Member
Just as an aside (and slightly off topic) I've also seen an old Schleicer PLC turn itself off if you used your mobile phone too close to it...
I haven't seen any of the modern PLC's affected by this but I think these kind of incidents in the past have helped fuel the current "no mobile phones in the factory" policy that a lot of UK factories have...
As for the welding issue, rsdoran is spot on, its due to a lot of current backfeeding into the device. The earth clamp needs to go near where the welding is taking place, but even then, as is the nature of electrickery, you can never be sure there won't be a problem. I would guess that tired old PLC's would be more susceptible than a newer model. Plus, newer models tend to build in backfeed protection (I've been told)...
I haven't seen any of the modern PLC's affected by this but I think these kind of incidents in the past have helped fuel the current "no mobile phones in the factory" policy that a lot of UK factories have...
As for the welding issue, rsdoran is spot on, its due to a lot of current backfeeding into the device. The earth clamp needs to go near where the welding is taking place, but even then, as is the nature of electrickery, you can never be sure there won't be a problem. I would guess that tired old PLC's would be more susceptible than a newer model. Plus, newer models tend to build in backfeed protection (I've been told)...