Delta PLC to LS VFD Modbus problem

Mufti

Member
Join Date
Apr 2011
Location
Amman
Posts
9
Attempting to connect PLC Delta DVP12SE to VFD LS SV075iG5A-4.
PLC COM2 LED is flickering but no response from Inverter :unsure:
This is my first attempt to use Modbus to communicate PLC with Inverter or Servo drive.
Screen shots + .dvp file attached to this post.
Tying to figure this out and I will post the solution when I find it.
Any advice would be highly appreciated :nodi:
-----
Connection ( 2-wire )
Delta-PLC LS-VFD
S+ S+
S- S-
-----
LS VFD Parameters:
Drv: 3(RS485)
Frq: 7(RS485)
I59: 0(Modbus RTU)
I60: 2(Inverter Modbus Address)
I61: 3(Baudrate 9600)
I62: 0(No-Action Lost Mode)
I63: 1(1 Sec Time-out)
-----
PLC ladder used is a modified ladder from Delta's Application Examples of Programming page 12-5
Link for pdf ( http://www.deltronics.ru/images/manual/DVP-PLC-101_A_EN_20120417.pdf )
-----
-----
Adjustments for ladder diagram:
* MODRD K1 H2102 K2 -----> MODRD K1 HA K2
Read Frequency from VFD to PLC
" H0x000A Output Frequency Address for LS VFD "
* MODWR K1 H2000 D10 -----> MODWR K1 H6 H2
Run FWD command to VFD
" Run Forward command H2 to Run Command Address H6 "
* MODWR K1 H2001 D11 -----> MODWR K1 H5 K4000
Set VFD Frequency to 40 Hz
" Set H5 Frequency reference to K4000=40Hz "
-----
Link for LS iG5A Inverter :
https://inverterdrive.com/file/LS-Starvert-iG5A-Manual
Communication Chapter 11
-----

Program 1.png Program 2.png Program 3.png
 

Attachments

  • Modbus1.zip
    11.8 KB · Views: 39
Tried to change VFD to modbus address 2 instead of 1 ( VFD Parameter I60 : 2 and PLC D1121 = K2 ).

Tried to SET and RST PLC-M1143 to change COM2 RS485 mode from ASCII to RTU since VFD works on RTU and LS-Bus modes.

Both attempts failed.
 
I tried adding a separate counters for flags M1127, M1129, M1140 and M1141.
All flags are from M1129 ( Communication time out flag )
 
Modbus scope reading

Connected the output of the PLCs COM2 to a scope and the signal seems OK.

modbus_fluke.jpg
 
Many thanks Parky for your reply, delta seems to have the same structure of registers and settings but with different numbers.

I found out that LS VFD protocol is totally different compared to Deltas. Mainly the issue was with special data register D1120(RS485 Com2 Protocol).

For Delta VFD it should be H86 (10000110) = 9600bps,7bit,even parity and 1 stop bit.

For LS VFD it should be H89 (10001001) = 9600bps,8bit,none parity and 2 stop bits.

I was able to send some MODRD instructions to read the model and capacity registers of the VFD and store on a data register on the PLC.

Still MODWR did not work yesterday. Although the only flag triggered when I ran the code was M1127(COM2 Rx-Tx Complete).
 
All done

Finally everything is working perfect now. MOWDR issue was with the LS VFD register address map, for some reason all addresses needs to be incremented by 1.

Example: 0x0004 is supposed to be parameter lock, turns out to be frequency reference. 0x0005 freq. ref. is actually operation command and so on.

A simply program was used to mod write a value of 4444 value into all memory map of the LS inverter, every register at a time with 1 second loop just to give time to visually inspect the screen of the inverter, once the 44.44hz was written to the inverter and appears on the screen it will be known that this is the frequency reference register. This is the only method I could think of to solve the memory address issue, after a few trials I found out the the memory map was all shifted up by one, maybe its a programming issue from my side I dont know and all I care about is that I can now make the PLC talk to the VFDs.

A working code is attached to this post.

LS Address.jpg
 

Attachments

  • Modbus Single LS VFD working.zip
    12 KB · Views: 80
Delta PLC to LS VFD Modbus proble

Hello
I have the same problem.
Resolved for you?
Is this file you sent correct?
Thank you for your help.:(
 

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