Winklehoffen
Member
Good god people! Please, please, pleeeeeease put the same number on both ends of the wire and - as Joshua said - terminals are just an extension of the wire. It is the quickest way of finding where a single wire terminates. Wire numbers should identify the wire, not necessarily the device it is connected to.
Using IO numbering is good but is not really any more effective than having a decent, easy to follow numbering system and falls over when you have multiple devices in an IO feed (e.g. 2 switches in series turning on an input).
Never rely on numbering based on drawings/schematics. More often than not the drawings are either buried in some managers office never to be located until some future archaeological expedition uncovers them, covered in oil and grease and therefore unreadable, not current due to modifications and changes in the past, or just downright lost. If your numbering system relies completely on the schematics then it is inherently flawed.
The best numbering system you can have is a logical sequential flow. Use the same number on both ends of the wire (and terminals). Use sequential numbering through a circuit (e.g. 1 to the stop button, 2 to the start button, 3 to the coil). Identify particular types of wiring with a prefix (e.g. different voltages have different prefixes, you could even use a prefix to identify a wire as a PLC input or output).
From what I have read on this forum, a lot of people seem to work in a happy utopia where drawings are readily available and constantly updated. In my 20 years of fault finding experience I have found this is very rarely the case.
There is not really any decent standard for panel wiring but please think of the poor sparky who, twenty years from now, has to follow each individual wire from point to point to figure out which contact has caked up with dust and is holding up production and costing the client thousands of dollars per minute (but making the sparky money, I guess).
P.S. The more important thing is that you do wire your labels. Anything will do really (as long as it is the same both ends). There's nothing worse than opening up a 4 meter long cabinet full of relays and contactors to find no labels on the wires.
Using IO numbering is good but is not really any more effective than having a decent, easy to follow numbering system and falls over when you have multiple devices in an IO feed (e.g. 2 switches in series turning on an input).
Never rely on numbering based on drawings/schematics. More often than not the drawings are either buried in some managers office never to be located until some future archaeological expedition uncovers them, covered in oil and grease and therefore unreadable, not current due to modifications and changes in the past, or just downright lost. If your numbering system relies completely on the schematics then it is inherently flawed.
The best numbering system you can have is a logical sequential flow. Use the same number on both ends of the wire (and terminals). Use sequential numbering through a circuit (e.g. 1 to the stop button, 2 to the start button, 3 to the coil). Identify particular types of wiring with a prefix (e.g. different voltages have different prefixes, you could even use a prefix to identify a wire as a PLC input or output).
From what I have read on this forum, a lot of people seem to work in a happy utopia where drawings are readily available and constantly updated. In my 20 years of fault finding experience I have found this is very rarely the case.
There is not really any decent standard for panel wiring but please think of the poor sparky who, twenty years from now, has to follow each individual wire from point to point to figure out which contact has caked up with dust and is holding up production and costing the client thousands of dollars per minute (but making the sparky money, I guess).
P.S. The more important thing is that you do wire your labels. Anything will do really (as long as it is the same both ends). There's nothing worse than opening up a 4 meter long cabinet full of relays and contactors to find no labels on the wires.