Hello everyone,

I am trying to improve my knowledge at reading wiring diagrams of control panels of machines such as conveyors, industrial ovens and stuff that have both high and low voltage. Youtube and google have not been very helpful because most of the materials on there are for generators or cars or low voltage electronic stuff.

I understand why manufacturers would not put control panel wiring diagrams in public otherwise people will just go and copy and make the product.
I'm only trying to learn so any control panel wiring diagram involving both high and low voltage, contactors, relays, inverters etc would be really helpful.
Please send to <clip>
Thanks in advance
Cheers

Edit: moderator removed email address to prevent spam. Also moved thread to General Electronics Chat

 

Here is a sample of ladder style symbols and control rungs etc. Telemecanique wiring diagrams
Generally most manuf. supply a wiring diagram of the system and enclosure, there is usually a pocket in the enclosure to hold the schematic for the use of on the floor maintenance personnel.
I see you are in UK but If you can get hold of a copy a NFPA79 it helps universally.
If pursuing this form of work, it would also help studying PLC's which have largely replaced the old style relay logic control for industrial shop floor automation etc.
Max.

 

Thank you Maxheadroom,

I do have some PLC programming knowledge using ladder, some function block diagram and statement list in Siemens S7 300.

But I have been to an interview and I was asked a question on a control panel, and given a wiring diagram and I froze. I left the inerview before recollecting I should have separated the control wiring diagrams from the power wiring to locate the fault. So I am very rusty in reading the diagrams which is why I'm trying to refresh my knowledge on it. I will google the NFPA79 and see what happens.

It's all about comfortably navigating the wiring diagram.

Cheers

 

Here is a sample of ladder style symbols and control rungs etc. Telemecanique wiring diagrams
Generally most manuf. supply a wiring diagram of the system and enclosure, there is usually a pocket in the enclosure to hold the schematic for the use of on the floor maintenance personnel.
I see you are in UK but If you can get hold of a copy a NFPA79 it helps universally.
If pursuing this form of work, it would also help studying PLC's which have largely replaced the old style relay logic control for industrial shop floor automation etc.
Max.

Hello Max,

Do you know of any material that teaches how to navigate wiring diagrams?

Thanks in advance.

 

Don't be too hard on yourself. I've been reading wiring diagrams, schematics, and ladder drawings for 50 years, and it's no surprise for me to take an hour to read a couple of pages, and then start doing measurements.

I can read a schematic faster than I can read English, and I'm a master at looking into a box full of colored wires and finding the one part that isn't working, but there is an incredible amount of information on a wiring page. Several people probably spent months designing and drawing. You can't be expected to understand it all in 5 minutes.

 

Apart from the NFPA document, I know if no manual specifically aimed at hard wired ladder diagrams, some of the PLC manuals show some of the methods, in spite of being ladder in software.
Ladder, whether hard wired or PLC is generally based on Boolean logic.
The N.A. and I believe UK still use the progression across the diagram from left to right, European method is from top to bottom and symbols are different, as shown in some of the Telemecanique link earlier.
There is one book by John Ridley "Mitsubishi PLC's" (UK) and describes logic methods that can also cross over into hard control, as well as being a useful PLC reference.
Max.

 

One method I used when I was called in to trouble shoot a machine was to ask the operator, where did it stop? IOW what was the next expected step.
This give a starting point as to where to look in any print, as to why a certain function did not complete.
If a machine appears dead, then obviously the place to start is in the power supply section, O/L's, fuses etc.
Max.