SCU 41 Modbus v7 Inverter

[andbert 0]

We're using: CJ1M CPU 13 SCU41 RS 485 4-wire Yaskawa V7 (3GMV) We're using modbus. How (where) do we set the speed for the inverter? We can make it go forward/backward, but only at the reference speed. To what register do we have to write so the modbus changes the frequency according to the program?

[ECSI 17]

set n004 = 6 (Frequency reference thru RS422/485 enabled) send reference to register 0002. This value is based on the units set in n0152

[beegee 7]

or send to register 0118Hex (this is parameter n024) and leave parameter n004

[andbert 0]

It work\0/, thank you very much:)

[ECSI 17]

Not sure on this but I thought you could only write to registers 0001,0002,0003, and 0009 and the rest are read only. Correct me if I'm wrong.

[andbert 0]

I used your advise ECSI, that worked fine, but does anyone know how to send more than one package? I'm using two inverters so I need to send 4 packages. One each to start the inverters, and one each to set the speed. I've attached the file I use for the modbus communication (CX-Programmer) Modbus_CJ1_RTU_Master_v2.cxp

 

Modbus_CJ1_RTU_Master_v2.cxp

[ECSI 17]

Check out the Broadcast Message feature. By setting the slave address to 00 in your message you are writing to all drives in the network. So, if you are setting the same speed on both drives then you could probably start the drives and set the speed all with one message.

[beegee 7]

you can write almost every parameter (some cannot be written during run ) You find the list in the manual ( next to the parameter list) but not with the broadcast message of course, for the parameters you need to address the inverter itself Edited 11 May 2007 by beegee

[andbert 0]

The inverters are running on different speeds. Now I'm trying to write a new FB that changes the registers it reads. It starts on D1000 to initialize the first inverter, then D1010 to initialize the second inverter, then D1020 sets the 1st speed and D1030 to set the 2nd speed. This block will count to 4 then reset to 0 so the speed will be updated whenever the value changes. Hope this works If anyone knows a better solution plz post it. I'll post later if it works...

[beegee 7]

instead of a broadcast, just make an incrementing program (with 1 as min and max address no as max) and write an indirect addreesed speed to the inverters. you can choose n004 at 6 and write to register 0002 or leave n004 and write register 0118. The choice is up to you. You do not really need to read the inverter's registers first. We do it like that on some of our machines (4 inverters and one CQM1H) I attached the protocols I wrote 5 years ago (we still use those) but the Modbus protocol is now available from Omron and will probably be better OMRPROTOCOL_AA.zip

 

OMRPROTOCOL_AA.zip

[andbert 0]

The program is running like a dream We have now a fully automatic ventilation program that can implemented in most systems with heating and cooling. The only thing a technician needs to do is adjust the PID values for each different system, which can be done by the HMI system (NS- touchscreen). Just need a few minor adjustment to make it run a little bit smoother... We made an incrementing program with a 0.02 s pulse for each step. n004 = 6 and the program writes to register 0002. Thank you everyone for the help!

[Chris Elston 78]

On 11/6/2021 at 4:20 AM, LD_M said:

Hello Admin/s,

Could you kindly fix this page, as some attachments are no longer available.

Thank you very much.

Did that work?

[LD_M 2]

Hi Chris,

Thank you very much.

The page is now fixed.