Control cabinet labels-best practices?

All things related to Centroid Oak, Allin1DC, MPU11 and Legacy products

Moderator: cnckeith

JasonPORC
Posts: 12
Joined: Wed Jan 27, 2021 11:30 am
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: none

Control cabinet labels-best practices?

Post by JasonPORC »

Good day all.

As I embark on my new cabinet for my Oak, I would like to hear about the choices people make about labeling. Yes, I know... label everything. But the nitty gritty of the question is where to start when numbering and lettering in and outs.

I get that L1 goes to T1 which then goes to U1 for example.
But what label do I put at then ends for the first wire here? Would I put L1 on both ends? Or L1 on one end and T1 on the other?

... On a schematic For example, how do you decide the number used for input 12 vs output 12? Or, what about when there are 4-24v commons? Do you just start from 1 and go until all the i/o has a number on it?

-Do you use even numbers for inputs and odd for outs?

-How do you somehow distinguish 5v and 24v? Is that something to take into consideration when mapping out and labeling the cabinet?

-What about heat shrink color choice?

Is there a universal “start here document” when labeling a control cabinet? If so, I’d love a link so I can read up on it.

I don’t want to over think this, but I’d like it to be correct and easy to understand when my old man brain tries to fix problems down the road.

Thanks in advance for any tips and tricks from the more experienced than me. Cheers!
cncsnw
Posts: 1873
Joined: Wed Mar 24, 2010 5:48 pm

Re: Control cabinet labels-best practices?

Post by cncsnw »

There are no doubt lots of different opinions on this subject. Here are mine.

1) Mark both ends of each wire with the same number, so that you can readily identify the other end of the wire when you see it.
1b) Do not just mark the end of each wire with the name of the terminal it connects to (which is, of course, different on each end).

2) Use at least 3-digit numbers. Choose series that are either related by voltage source (e.g. 100's for all the 120VAC circuits, 900's for all the 24VDC input circuits, etc.) or are related by function (e.g. 400's for all the PLC input circuits; 500's for all the PLC output circuits; etc.).

3) For line-level AC power distribution (i.e. 240VAC in a 240V cabinet, 480VAC in a 480V cabinet) the US/NEMA convention is "L1, L2, L3" for the three power legs, and prefixes that change each time you go through an intermediate switching device (e.g. 1L1, 1L2, 1L3 after the main circuit breaker; 2L1, 2L2, 2L3 after you go through a smaller circuit breaker on the way to a motor controller, etc.). In that system, the final run from the motor controller to the motor itself is then a prefix on T1, T2, T3 (e.g. 2T1, 2T2, 2T3 going from the motor starter or VFD to motor #2).
3b) Alternately, the convention in many other parts of the world is R, S, T with a suffix for power distribution (e.g. R1, S1, T1 coming out of the main breaker, then R2, S2, T2 from a smaller breaker to a controller); and U, V, W with a suffix for the final run to the motor (e.g. U2, V2, W2 going from the starter or VFD to motor #2).

4) Don't worry too much about heat shrink color, but do pay attention to wire color. Common conventions are:
BLK = line-level power distribution
RED = AC control circuits (usually lower voltage than incoming lines)
WHT = AC neutral ("grounded current-carrying conductor")
BLU = DC circuits, whether power or control
BLU/WHT (optional) = grounded current-carrying DC conductors
GRN or GRN/YEL = safety grounds
ORG = "Foreign" circuits powered from an external source, which may therefore be live even when power to this panel is turned off
4b) Of course, when you use multi-conductor cable, you will use whatever colors are in it. The above are just for discrete wires.
4c) In those rare circumstances where I have both 24VDC circuits and 5VDC circuits, and the 5VDC does more than just go from (for example) the Oak's logic power supply to the Oak's logic power header, then I will sometimes use RED and BLK for the +5VDC and 0VDC wires, and expect that they can be distinguished from AC power and control circuits by being smaller gauge, as well as by a distinct number series. More commonly, though, I use BLU for both 5VDC and 24VDC, and distinguish them only by separate wire number series.

5) Draw up a your own schematic or connection diagram, showing all of your wires and their numbers. Regarding (1b) above: probably the reason some builders mark every wire end with the name of the terminal that it connects to, is so that an unskilled person with no wiring diagram can replace a component, and probably get the wires reconnected in the right places. You can address that need by providing a good wiring diagram instead.

6) I prefer to use the same number for every wire that carries exactly the same signal. For example, if the 0VDC side of the PLC inputs 24V supply is numbered 400, then when I connect that signal -- with no intervening fuses, switches, etc. -- to a device (say, a limit switch common) then the wire to the device is still #400. In other words, I do not change wire numbers just because I have landed on, and departed, a distribution terminal. This simplifies the numbering, and make it easy to know what a given wire is carrying. On the other hand, this makes it harder to tell where a given wire (e.g. 400 BLU) goes to. Others (including those who draw the Centroid factory schematics) use a distinct wire number for every run, even when multiple runs originate at the same point (again, the 0VDC side of the PLC input supply, and 120VAC neutrals, are the most prolific examples). This makes it easier to identify the purpose of a given wire (e.g. wire #128 is the 120VAC neutral going to the lube pump, while wire #109 is the 120VAC neutral going to the cabinet fan) but it requires a lot more wire numbers.

Don't get too ambitious about a grand unified wire-numbering plan. Inevitably, you will run into exceptions that break your design. For example, if each PLC input point has a certain wire number assigned to it, then what do you do when an input is connected to two or three switches in series? You need additional numbers for the wires running between the switches. The most important thing is to have a distinct number for every wire that serves a unique function; mark both ends of the wire; and put that number on your wiring diagram so you can look it up later.
JasonPORC
Posts: 12
Joined: Wed Jan 27, 2021 11:30 am
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: none

Re: Control cabinet labels-best practices?

Post by JasonPORC »

cncsnw wrote: Sat Feb 13, 2021 6:40 pm There are no doubt lots of different opinions on this subject. Here are mine.

1) Mark both ends of each wire with the same number, so that you can readily identify the other end of the wire when you see it.
1b) Do not just mark the end of each wire with the name of the terminal it connects to (which is, of course, different on each end).

2) Use at least 3-digit numbers. Choose series that are either related by voltage source (e.g. 100's for all the 120VAC circuits, 900's for all the 24VDC input circuits, etc.) or are related by function (e.g. 400's for all the PLC input circuits; 500's for all the PLC output circuits; etc.).

3) For line-level AC power distribution (i.e. 240VAC in a 240V cabinet, 480VAC in a 480V cabinet) the US/NEMA convention is "L1, L2, L3" for the three power legs, and prefixes that change each time you go through an intermediate switching device (e.g. 1L1, 1L2, 1L3 after the main circuit breaker; 2L1, 2L2, 2L3 after you go through a smaller circuit breaker on the way to a motor controller, etc.). In that system, the final run from the motor controller to the motor itself is then a prefix on T1, T2, T3 (e.g. 2T1, 2T2, 2T3 going from the motor starter or VFD to motor #2).
3b) Alternately, the convention in many other parts of the world is R, S, T with a suffix for power distribution (e.g. R1, S1, T1 coming out of the main breaker, then R2, S2, T2 from a smaller breaker to a controller); and U, V, W with a suffix for the final run to the motor (e.g. U2, V2, W2 going from the starter or VFD to motor #2).

4) Don't worry too much about heat shrink color, but do pay attention to wire color. Common conventions are:
BLK = line-level power distribution
RED = AC control circuits (usually lower voltage than incoming lines)
WHT = AC neutral ("grounded current-carrying conductor")
BLU = DC circuits, whether power or control
BLU/WHT (optional) = grounded current-carrying DC conductors
GRN or GRN/YEL = safety grounds
ORG = "Foreign" circuits powered from an external source, which may therefore be live even when power to this panel is turned off
4b) Of course, when you use multi-conductor cable, you will use whatever colors are in it. The above are just for discrete wires.
4c) In those rare circumstances where I have both 24VDC circuits and 5VDC circuits, and the 5VDC does more than just go from (for example) the Oak's logic power supply to the Oak's logic power header, then I will sometimes use RED and BLK for the +5VDC and 0VDC wires, and expect that they can be distinguished from AC power and control circuits by being smaller gauge, as well as by a distinct number series. More commonly, though, I use BLU for both 5VDC and 24VDC, and distinguish them only by separate wire number series.

5) Draw up a your own schematic or connection diagram, showing all of your wires and their numbers. Regarding (1b) above: probably the reason some builders mark every wire end with the name of the terminal that it connects to, is so that an unskilled person with no wiring diagram can replace a component, and probably get the wires reconnected in the right places. You can address that need by providing a good wiring diagram instead.

6) I prefer to use the same number for every wire that carries exactly the same signal. For example, if the 0VDC side of the PLC inputs 24V supply is numbered 400, then when I connect that signal -- with no intervening fuses, switches, etc. -- to a device (say, a limit switch common) then the wire to the device is still #400. In other words, I do not change wire numbers just because I have landed on, and departed, a distribution terminal. This simplifies the numbering, and make it easy to know what a given wire is carrying. On the other hand, this makes it harder to tell where a given wire (e.g. 400 BLU) goes to. Others (including those who draw the Centroid factory schematics) use a distinct wire number for every run, even when multiple runs originate at the same point (again, the 0VDC side of the PLC input supply, and 120VAC neutrals, are the most prolific examples). This makes it easier to identify the purpose of a given wire (e.g. wire #128 is the 120VAC neutral going to the lube pump, while wire #109 is the 120VAC neutral going to the cabinet fan) but it requires a lot more wire numbers.

Don't get too ambitious about a grand unified wire-numbering plan. Inevitably, you will run into exceptions that break your design. For example, if each PLC input point has a certain wire number assigned to it, then what do you do when an input is connected to two or three switches in series? You need additional numbers for the wires running between the switches. The most important thing is to have a distinct number for every wire that serves a unique function; mark both ends of the wire; and put that number on your wiring diagram so you can look it up later.
THANK YOU CNCSNW!!!!! This is super helpful. And it makes me happy knowing there’s no real “standard” that I’m missing. I really like the idea of grouping numbers based on voltage or usage. Great tip!

It’s clear based on your answers that the first couple small cabinets I did were...”made by a novice” so to speak. My shrink tubing said where it was going or coming from. Oops. All we can do is learn right? 😊.

It’s also clear now about the line voltage labels. I’ll keep that in mind when going through contractors and VFDS.

Any other tips out there to go along with these????? I’d love additional feedback so I can find a system that works for me! Thanks again!
cncsnw
Posts: 1873
Joined: Wed Mar 24, 2010 5:48 pm

Re: Control cabinet labels-best practices?

Post by cncsnw »

JasonPORC wrote:My shrink tubing said where it was going or coming from. Oops. All we can do is learn right?
If you mean that you marked each wire end to tell where to find the other end of that wire, that method has a lot of merit. My peeve/rant is against marking each wire end to show where this end connects. The latter is no help at all in tracing a circuit. Your method would lead, step by step, from one end of the circuit to the other.

Imagine you are troubleshooting an issue with the emergency stop contactor coil circuit in an older Centroid M39S DC-servo control. 24VAC starts at the transformer; goes through an EMI filter; goes through a fuse; goes through the fault relay on the SERVO3IO or DC3IO; optionally goes through another fault relay on a DC Single or DC1; goes through the emergency stop pushbutton in the pendant; then goes to the contactor coil. The other side of the contactor coil continues back through the EMI filter to the transformer. If the machine features additional emergency stop pushbuttons, they might be introduced in the circuit, in series, at any point. You want a marking scheme that will allow you to follow the circuit from end to end, so you can find the place where it is open.
DannyB
Posts: 109
Joined: Mon Jan 15, 2018 1:11 am
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: Yes
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: A900712

Re: Control cabinet labels-best practices?

Post by DannyB »

+1.

It doesn't make any sense to label things with the terminal they connect to.
If you label each end with where they come from (IE label the side going into a signal "from 24v power supply" and the side going into the 24v power supply with "to signal #123"), you can both put it back together properly and know where the other end can be found.
tblough
Posts: 1340
Joined: Tue Mar 22, 2016 10:03 am
Acorn CNC Controller: Yes
Allin1DC CNC Controller: Yes
Oak CNC controller: Yes
MPU11 & GPIO4D -w/ 3rd Party Drives: Yes
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: 100505
100327
102696
103432
7804732B977B-0624192192
Location: Boston, MA
Contact:

Re: Control cabinet labels-best practices?

Post by tblough »

I'm from the each wire has a unique number and is marked on each end camp.
Cheers,

Tom
Confidence is the feeling you have before you fully understand the situation.
I have CDO. It's like OCD, but the letters are where they should be.
JasonPORC
Posts: 12
Joined: Wed Jan 27, 2021 11:30 am
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: none

Re: Control cabinet labels-best practices?

Post by JasonPORC »

Thank you all!!!!!!
tblough
Posts: 1340
Joined: Tue Mar 22, 2016 10:03 am
Acorn CNC Controller: Yes
Allin1DC CNC Controller: Yes
Oak CNC controller: Yes
MPU11 & GPIO4D -w/ 3rd Party Drives: Yes
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: 100505
100327
102696
103432
7804732B977B-0624192192
Location: Boston, MA
Contact:

Re: Control cabinet labels-best practices?

Post by tblough »

tblough wrote: Mon Feb 15, 2021 2:45 pm I'm from the each wire has a unique number and is marked on each end camp.
Here's and example schematic with that wiring scheme. I find this method easier for troubleshooting when I have a schematic. If I'm having problems with the coolant solenoid, I can see from the schematic that in need to check on wires 34 and 94 and that 34 should be line neutral.

Marc's method of numbering wires according to function is very helpful when you try to troubleshoot a machine without a schematic. If i see wire 40 connected to the +24 terminal of the logic power supply, then I know every wire labeled 40 should have +24V on it.

Both methods have their pros and cons. Pick one that works for you and follow it. Any wire numbering scheme is far better than no numbering scheme!
Attachments
VCL-1062J011-CNC Schematic.pdf
(564.52 KiB) Downloaded 16 times
Cheers,

Tom
Confidence is the feeling you have before you fully understand the situation.
I have CDO. It's like OCD, but the letters are where they should be.
JasonPORC
Posts: 12
Joined: Wed Jan 27, 2021 11:30 am
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: none

Re: Control cabinet labels-best practices?

Post by JasonPORC »

tblough wrote: Wed Feb 17, 2021 12:22 pm
tblough wrote: Mon Feb 15, 2021 2:45 pm I'm from the each wire has a unique number and is marked on each end camp.
Here's and example schematic with that wiring scheme. I find this method easier for troubleshooting when I have a schematic. If I'm having problems with the coolant solenoid, I can see from the schematic that in need to check on wires 34 and 94 and that 34 should be line neutral.

Marc's method of numbering wires according to function is very helpful when you try to troubleshoot a machine without a schematic. If i see wire 40 connected to the +24 terminal of the logic power supply, then I know every wire labeled 40 should have +24V on it.

Both methods have their pros and cons. Pick one that works for you and follow it. Any wire numbering scheme is far better than no numbering scheme!
Thanks Tom! That’s incredibly helpful to see how you laid this out. Now my question is how did you do this on the pdf from centroid? Just drawing a schematic is yet another thing to learn. All of my current hand drawn ones look like that of a 3 year olds art project. Ha ha.

Again, thanks for chiming in again. I appreciate it!
tblough
Posts: 1340
Joined: Tue Mar 22, 2016 10:03 am
Acorn CNC Controller: Yes
Allin1DC CNC Controller: Yes
Oak CNC controller: Yes
MPU11 & GPIO4D -w/ 3rd Party Drives: Yes
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: 100505
100327
102696
103432
7804732B977B-0624192192
Location: Boston, MA
Contact:

Re: Control cabinet labels-best practices?

Post by tblough »

I drew those from scratch in AutoCad Electrical since I had access to it. There have been a few threads on here about drawing schematics. You can do it in any CAD package (including free ones like SketchUp and FreeCAD). People have used Visio and other office graphing programs and Electronics schematic programs like KiCAD and Eagle PCB.
Cheers,

Tom
Confidence is the feeling you have before you fully understand the situation.
I have CDO. It's like OCD, but the letters are where they should be.
Post Reply