CPM2A and inverter F7

[elem 0]

I am a beginner, an I want to make a Profibus system with components specified from a third party. It is shown on the picture below, but I don't know how to connect CPM2A (slave) with inverter F7. Can it be done with a simple serial connection? What do I need to establish it? Is there a function block for this (stop, start, changing speed)? It's very urgent, please help.

[gtsuport 61]

elem, Welcome to the forum! Based on what I found for communication protocols for the F7 inverter, I think you are going to have a tough time with serial comm using a CPM2 plc. It appears that the serial comm would probably be some form of Modbus. What about using hardwired I/O? You could use outputs to send start/stop and an analog output for speed command. However, I really do not know the details of your application. If you really want to do this with communication, you might consider a CJ1 and use protocol macros with Modbus. Hope this will help

[elem 0]

gtsuport, thanks for welcoming me. I've just discovered this forum, hope I'll learn some usefull stuff here. This little work of mine is going to be "hanged" on a wall as a demo example. This is the first time I'm setting up a Profibus network, so I decided to make something simple for now and see if it works, and then try to make it more applicable. I personally wanted to use CJ1, but "the boss" wants CPM2A, so there is no changing the rules of the game :( Actually, I was thinking of Memobus. In User's manual for F7, there is an explanation on page 6-80. I've just found it and I'm going to read it tonight, but what I want to know is: Can I use it with CPM2A? More important question is: Is there a function block for it, so I dont need to do too much programming? (start, stop and frequency through PT) As I said I'm a total beginner

[gtsuport 61]

The CPM2 does not support function block programming, only CJ1/CS1 processors support function blocks. The next challange will be building the correct character strings in the plc. This will probably include some sort of frame checksum or block checksum for the communication string. The math is fairly limited on the CPM2. In addition, all ASCII in the CPM2 would need to be handled as HEX. Each DM can hold 2 characters. Your project may be possible, but will require quite a bit of advanced programming IF it is possible. I understand that this is not good news for you. I will be away from the office next week, so will not be checking this forum. Did not want you to think you were abandoned. Good Luck!

[elem 0]

thanks for help, gtsuport. Very usefull answers. I'll be back with more questions, soon. Hope there will be someone to help me when you are not here.

[PdL 71]

If my memory serves right you can also use Modbus commands for Memobus. btw, thought I was the only one blessed with such art skills

[Sleepy Wombat 27]

As has been suggested, to develope the Modbus protocol in a CPM2A is no easy task, I would of opted for a small CJ with a serial module using protocol macro modbus protoctol. But if you are able to sting this out for a bit i suggest that you take a look at the new CP1H due for release any minute now, worst case being first quarter of 2006. cp1h

[banker 2]

Hello Elem You can get a Profibus slave card for the F7 inverter. Then the master PLC can make the start / stop and speed change. The slave PLC can send the demand to the master. Banker

[elem 0]

I have that card for F7. How do I connect the slave PLC than?

[elem 0]

I injured both hands and my right foot, so I had to do it with my left foot. Sorry :)

[banker 2]

Elem You can set the PRM21 as a master. The CPM2A (PRT21) and the F7 works as slaves. You can the send run request, stop, speed from the CPM2A to the F7 via the master PRM21. You will need the software CX-profibus to setup the network. Banker

[pycathiu 0]

hi,this is the programm of cpm2a use peripheral port & RS232c PORT to communication with V7.refer to it CPM2AH_Inverter.rar