Matchu04
Lifetime Supporting Member
As my confidence grows with working with multiple control systems, I am starting to take more and more on, where before I would just pie it off. (I would like to say this is mainly due to the help from you guys on this site). I have managed to trip my self up a few times along the way in simular situations and hence require some guidence from you guys once again.
My Issue..
I recently had to verify a flow meter (a E&H 53p80 for those who are interested) and for for what ever reason it failed and had to replace it. My issue came when disconnecting the feed back loop cables. I was under the impression that as the unit had 24v to it, it would used this to power to loops. So removing this supply would isolate it. However when I disconnect them, after isolting the 24v supply, I soon realised that this wasnt the case and shorted them out against some main beer line and needless to say a 20 min job just got longer.
Is this my fault for assuming...? Are feedback loops normally fused inside the main panel to protect the PLC so should have isolated it there.
How would you guys go about it?
My Issue..
I recently had to verify a flow meter (a E&H 53p80 for those who are interested) and for for what ever reason it failed and had to replace it. My issue came when disconnecting the feed back loop cables. I was under the impression that as the unit had 24v to it, it would used this to power to loops. So removing this supply would isolate it. However when I disconnect them, after isolting the 24v supply, I soon realised that this wasnt the case and shorted them out against some main beer line and needless to say a 20 min job just got longer.
Is this my fault for assuming...? Are feedback loops normally fused inside the main panel to protect the PLC so should have isolated it there.
How would you guys go about it?