Please Can any one Resolve the following issues while communicating with A1000 Drive 

Attachment 1 :Busy status is stuck on True

Logic is written in Step 7 v13 SP1

PLC ; 1214C DC/DC/RLY

Hello Sahish.

The FBs linked to %DB5 is writing over each other. There is a sequencing issue that needs attention.

Have a look at:
https://support.industry.siemens.com/cs/document/63696870/

Focus on the software technique (sequencing) and understand the comments on the hardware connection. Look at ALL the documentation that has to do with Modbus RTU from the web link: x2 PDF and PLC project.

Know that the Yaskawa documentation can be confusing on the addresses. I have seen two address numbers for the same thing in the same document (V1000).

Siemens start from "1". If your address list starts at "0" then you need to +1 for all the addresses. If it starts at "1", you should be okay. Just ensure you use the same list at all times.

Note if the address is given in HEX or decimal. The addressing you have in your program is in decimal. So if you encounter HEX, then convert it.

On your convert FBs that goes from BITS <-> WORD:
(Taking FB2 as example)

1. You can use an FC no FB required
   
   
2. Note that #statReads[0] is not the least significant bit. #statReads[8] is the least significant.
   
   
3. To continue using the AT overlay, you need to use SWAP.
   
   
4. #Write.%X0 is the least significant bit. This technique is called SLICING. The PLC manual explains this and FAQ exists on the web too. The AT overlay is not required.
   
   

Please consider next time to include your code piece within your message. ZIP is accepted. You could archive the project within TIA Portal to a ZAP13 file and then ZIP before adding to your message.

Bye.
- Dan

Thanks Dan for your propmt reply, I checked the modbus communication over modscan. I was unable to write refrence frequency to drive even though i had B1-01 and B1-02 settings set for modbus communication. Also the last bit in 40002 holding register was sending vfd start command and on 40033 i could monitor the 3 responses i wanted. This was all done through Modscan. But i will do make some changes you mentioned and look into bit slicing.

Hello Sahish.

The code in the PDF seems okay, after a quick inspection No further comment on the coding at this time. Some helpful general thoughts follow.

Be wary of coding the whole solution without confirming the foundation first. That can be done with some small tests.

There is no need for B1-01 and B1-02 to be set for Modbus control. Without it Modbus comms can still access parameters in the drive.

I use this idea at times. I set the drive to work in "normal" way and then Modbus manipulates d1-01 to the required internal speed setpoint as needed. There are several advantages to this when doing transport systems.

Use the same idea for experimentation. Make manual adjustment in the drive. Example: d1-01 = 12.34Hz. Then try to read d1-01 by the PLC with Modbus using a smaller scaled program. This confirms the foundation as well as Modbus addressing and byte orientation.

(Not specifically to the A1000 but in general to sorting out comms to a device.) When reading from a "known" source some insights are gained. The address might need a +1 bias to get the right address. Sometimes two bytes needs to be swapped. Other times the value is prescaled to some maximum number and what you read is a percentage.

Bye.
- Dan

Hey there Dan, Thanks again for your valuable inputs.

I had established a modbus connection with VFD using Modscan and it wasn't allowing me to write data over modbus unless i set B1-01 & B1-02 for modbus communication. I have already found out the addresses where i have to READ and Write data using Modscan and i am using those same addresses in my logic.

in case of memobus if we are reading or writing LongWord then the bytes need to be swapped, if it's boolean bits of a word then it is completely mirrored or reversed and if it's an analog int value then no need to swap or reverse.

source:

https://www.google.co.in/url?sa=t&source=web&rct=j&url=https://www.yaskawa.com/delegate/getAttachment%3FdocumentId%3DTN.MCD.01.013%26cmd%3Ddocuments%26documentName%3Deng01013%2520-%2520Modbus%2520vs%2520Memobus.pdf&ved=0ahUKEwjA7fiik7zTAhUKwI8KHbngDBsQFggeMAE&usg=AFQjCNEYOu_E6XAHMT8F3nOZ0uCP0VT07w&sig2=04uK1J9KtU57cSthuNeCKw

Hello.

There is no concrete reason to question your statements. The scrambled bits you mention, does not make sense.

Do realise that what you see in ModScan might not be the same as on the PLC. Controlling the drive and making parameter changes over Modbus are two different things.

I do hope and trust you'll make a success of your project.

Bye.
- Dan