OPC UA node can't be written to

Greetings everyone,

my problem occurs in using a Bachmann M1-Device to set up a robot control. The control is implemented in Simulink and built to the device using automatic code generation, which works flawlessly. In order to test some things out, i wrote a .m-file to basically simulate the robot. Im using the OPC UA commands to read from and write to the control-programm on the device. Therefore, i specified SVI-Read and SVI-Write Blocks in the Simulink file.

I establish a connection using

uaClient = opcua(IPAdress,Port)

connect(uaClient)

Im then creating the node-objects to read and write values with

node_q_lin = findNodeByName(Namespace,'hOPCUAq_lin','-once')

.

AccessLevelCurrent: read/write

.

In Simulink, hOPCUAq_lin is a SVI-Read Block. Data type is specified as inherited, initial value is set to [0 0 0 0 0]. Reading from the node delivers

readValue(uaClient,hOPCUAq_lin)

=[0 0 0 0 0].

So far, so good. But if i try to write a value into the node with, the following error occurs

writeValue(uaClient,node_q_lin,[0 0 0 0 0])

Error using opc.ua.Client/writeValue (line 1268)

The value supplied for the attribute is not of the same type as the attribute's value.

This seems quite strange to me, and i don't really have a clue to what went wrong here. I have not found a similar scenario in the documentation so far, but i will keep on looking. I would greatly appreciate any suggestions.

Answer 1

[Boris Blagojevic]

I solved the issue. Turns out, that the documentation provides the necessary information.

A vector-valued variable hOPCUAq_lin with 5 dimensions will be saved as

hOPCUAq_lin

hOPCUAq_lin[0]

....

hOPCUAq_lin[4]

where hOPCUAq_lin[0]...hOPCUAq_lin[4] address to the dimensions of the variable. They can be found in the namespace by using findNodeByName(Namespace,'hOPCUAq_lin','-partial')