Newbie looking for some wiring help

[paulie walnuts]

Hi there. I am new to the electrical game and was wondering if anyone could help me in a college project.
I am trying to connect a variable speed drive to a PLC but I'm unsure of where the wires go. I've attached a diagram of the wiring configuration. So far I have wired the +24V terminal to the PLC and also the digital inputs to the plc outputs. What is confusing me is the idea of the reference voltage. If anyone can make sense of this I would really appreciate some advice that might point me in the right direction.

Thanks in advance!

 

[Knobhead]

What output card are you using for the PLC? From your drawing it can be either 0-10V or 4-20mA you just assign the input in the drive parameters. Basically you just have two wires to worry about. I’ve always used 4-20mA but only because we carried the PLC cards as stores stock.

Looks a fun project.

The fun and games start when you have a feed back loop and you have to start playing with PID control.

 

[paulie walnuts]

I'm not sure what you mean by output card? I have an analog output signal board. Should I be drawing the +24V and the 10V Ref from the PLC?

 

[Knobhead]

4to20mA or 0to10V from the output board. 24V is internal to the drive.

 

[paulie walnuts]

I don't understand, if i'm taking 0-10v from the output board (analog output terminal) then what do I connect the analog input from the VSD to?

 

[Knobhead]

The analog output of the PLC.

 

[Knobhead]

What type of PLC and drive are you using?

 

[paulie walnuts]

Siemens 1200 PLC and a Parker 650 VSD.

Are you saying that the 10V Ref and the Analog input (of the VSD) are both connected to the analog output of the PLC?

 

[Knobhead]

Have you looked at their web sites? Why aren’t the course lecturers giving more assistance?
I’m sorry but I find it hard to believe you’ve been let loose with this kit without more direction being given.

 

[paulie walnuts]

Ha you don't need to tell me that. My background so far has been in PLC programming and very little in the way of hardware configuration etc.

 

[Knobhead]

So if your done the programming before you must know how the configure the PLC. I’ve mainly worked on Modicon, the O/P cards would be assigned a register. The value in that register would determine the analogue output 0 = 4mA or 0V Min, 4095 = 20mAor 10V Max. This output would go to the VSD analogue input for the speed control. As for the start stop commands I cheated, Modicon had switched volt free output cards, which I used for start and stop. This card switching the VSD’s 24V control. Another cheat was that once the machine was in run condition the 24V wasn’t used again. Starting and stopping being carried out by changing the register value 0 = stop, xxxx = whatever speed you wanted. The main machines I worked on the centrifuge drive would run at six different speeds during each cycle. With the centrifuge weighing 35tons I could stop it quicker using the ramp down and regenerative braking on the drive than the normal start/stop, and do less damage.