Identifying cables from proxy to plc

[Shaun12]

Looking inside a panel i noticed the 0v and 24v from a sensor went to a row of terminals before the I/O. They were labelled up h1 24v (brown) and a h2 0v (blue). I was just wondering why h1/h2 instead of 24/0v? Is this simply just how the designer chose to identify them or does the h mean something else?

 

[netblindpaul]

60079?

 

[Bobster]

60079?

Looks right, I know that is a hazardous area standard. Not sure if it's the one that covers panel wiring colours.

I should know, I have a copy perched on the end of my table in the office.

 

[netblindpaul]

Looks right, I know that is a hazardous area standard. Not sure if it's the one that covers panel wiring colours.

I should know, I have a copy perched on the end of my table in the office.

I'm still in the bloody office!

 

[shanky887614]

Following 60204 they've used the colour allocated to I.S wiring.

Those don't look like terminals, more like slim line relays. Maybe used to interpose between the PLC and the field device.

your right rob it does look like relay carrier's i cant see any other terminals for the relay which is strange unless its hidden in view

 

[Bobster]

your right rob it does look like relay carrier's i cant see any other terminals for the relay which is strange unless its hidden in view

From the looks of it, using a similar relay base to these.