modbus - example error

[anprzy]

Hello,

i downloaded NI Modbus library and started MB Ethernet Example Slave and MB Ethernet Example Master. But when i start Master im getting error:

Error 56 occurred at TCP Read in MB Ethernet Receive.vi

LabVIEW:  The network operation exceeded the user-specified or system time limit.

Open TCP connection is ok, but when it goes to MB Ethernet Master Query Read Discrete Inputs im getting error.

I work with other PLC and i need to connect via Modbus - but i really have no idea how to test Modbus when even example didn't work.

I appreciate if someone can tell me how to test Modbus properl.

[e2m0i0l7]

Hi,

Seems you have recieved a timeout error, because of the connection.

I would recommend you tested it like that:

1.Open both Master and Slave in LV.

2.In master set the remote ip address: localhost

3.Execute slave, execute master

Perform changes on the master, and see the functionality on the slave, and vice-versa.

Good luck,

Mircea