Communication ModBus TCPIP Error 6004

[Willem1978]

I'm getting error 6004 Modbus Exception code: 4.

I'm trying to connect to  a Beckhoff BK9050 with 16 output KL2809 and 16 inputs KL1809.

I used a VI from the Modbus library (MB Ethernet Example Master.vi).

When I start, everything seems to work. I can control the outputs and I can read the inputs in my program.

But when I stop the program and start it again, then the error 6004 exception code 4 arrives when I will control an output. What can cause this problem?

Thanks in advance for the support.

[Willem1978]

I'm getting error 6004 Modbus Exception code: 4.

I'm trying to connect to  a Beckhoff BK9050 with 16 output KL2809 and 16 inputs KL1809.

I used a VI from the Modbus library (MB Ethernet Example Master.vi).

When I start, everything seems to work. I can control the outputs and I can read the inputs in my program.

But when I stop the program and start it again, then the error 6004 exception code 4 arrives when I will control an output. What can cause this problem?

Thanks in advance for the support.

[RavensFan]

Modbus exception 4 is an error within the slave device.  It couldn't do what it was asked so it is responding back with that message.

It is not a problem with your LabVIEW code, but a problem with the slave device.

You'll need to contact Beckhoff for help on that.

[Willem1978 · Accepted solution]

Thanks for your reply.

I have solved the problem.

The problem was that the Beckhoff module had a Watchdog error when I stopped my VI.

Now I reset the Watchdog Timer just before I close the VI by transfering 0xBECF and 0xAFFE to register 0X1121.

I got it from http://forums.ni.com/t5/forums/v3_1/forumtopicpage/board-id/170/thread-id/518237/page/1.

[பரத்_குமார்(bharathkumar)]

Hello RavensFan,

I am trying to communicate with Oriental Motor using Modbus Protocol. But I am getting 6004 Error.

Is it because I am sending the command Incorrect?

[RavensFan]

All we can see is your front panel.

But one thing I see is that you have "Write Single Register" but the quantity to write is set to 2.

[பரத்_குமார்(bharathkumar)]

Hello RavensFan,

Thanks for the reply. Sorry I did not attach the VI. I am trying to drive Rksd507-cd Driver from Oriental motor by modbus. Learning modbus. and looking for more examples. Any library will be helpful.(Oriental motor with LabVIEW is so hard):smileymad:

any link to modbus example will be helpful(Communicating with adam4561 serial converter).