kinetix 3 and micrologix 1400

[hackj0632]

i have a question with the communication between the micrologix 1400 and a kinetix 3 servo drive. i have several read and write message being sent to the K3 drive. i have two message instructions that are giving me some issues. in the message monitoring screen in RSLogix i received a hex error code of 89 with a message (mod-bus non-standard exception code returned( exception code >8)). i downloaded the sample code off of AB website and downloaded to the micro with the same error code.

any ideas would be appreciated.

in particular i receive this error on the write message.

 

[Ken Roach]

From my brief reading of the Host Protocol manual (2071-RM001), Modbus address 43001 is the middle of three Input Function Parameters.

If you perform a Function 16 (Write Multiple Holding Registers) with a length of 3, it's going to write to 43001, 43002, and 43003.

But 43001 doesn't appear to be defined, so it's possible that's the problem.

Try a Function 6 to register 43001, or try using that Function 16 starting at 43000.

I admit I'm not familiar with the Kinetix 3, and the "0 vs. 1" Modbus addressing issue has flummoxed programmers for generations.

 

[hackj0632]

i tried several variations, with some different results. if you notice i receive a different error code.

i appreciate the help.

side note, i downloaded a sample indexing program off the AB website that had the same messaging setup as i posted previously.

 

[DamianInRochester]

On the second one you appear to be trying to write to a read only variable.


EDIT: Never mind ---- I goofed

 

[DamianInRochester]

Page 13 of the document
http://literature.rockwellautomation.com/idc/groups/literature/documents/rm/2071-rm001_-en-p.pdf

seems to be suggesting that for modbus addresses 3000, 3001, and 3002 that that range only supports Function codes 3,6, and 10.

Regardless, you are starting a 3001 and have an element size of 3, so your trying to write to 3003 which does not exist.


Try just setting the element size to 1.
Try also changing it to Function code 6 with an element size as 1.

The example looks as though it may be wrong.

 

[hackj0632]

illegal data address

 

[DamianInRochester]

illegal data address

Can you try with all the same settings only with address set to 3001?

 

[hackj0632]

3001 must be an input register. this is the msg instruction for 43001. no errors.
i dont understand why they say you can use function 03 06 10 if its not allowed to be written too.

 

[Ken Roach]

We probably have a Modbus addressing issue as well as a configuration issue.

I agree that these registers look like they should be writable; they have function names like "Drive Enable" and "Start Homing".

Is it possible that the Kinetix 3 will return an error if these functions of the drive are mapped, linked, or assigned to something other than the serial interface ?

The Modbus addressing in the Kinetix 3 user manual starts at "Modbus Address 0", whereas RSLogix 500 uses the convention that the first Modbus address is 1.

Kinetix 3   RSLogix 500    Inside Modbus Packet
0             40001            0
1             40002            1
2             40003            2
...            ...                 ....
2999        43000            2999
3000        43001            3000
3001        43002            3001
3002        43003            3002
3003        43004            3003

This is why the MMS_056336 example writes B111:0,1,2 to "Modbus Address 43000" in the Kinetix 3 by configuring the MSG instruction to write to "Modbus Address 43001".

The example code looks correct to me, which brings us back to your original screenshot and the nonstandard exception code.

Have you run this by RA Technical Support ?

 

[hackj0632]

yes i called our local distributor and he suggested that i call as well. little did i know you need to have some contract with them to get any technical support. hence the post on plc.net to begin with.

thanks for asking though.

 

[hackj0632]

i was paging through the user manual and notice the descriptions of the firmware update. i checked the drive which were labeled 2.00 the latest firmware revision was 2.20. i searched the AB website with no luck. if you could help me find the latest firmware zip file this might help.

thanks