adccommunitymod (AutomationDirect) asked a question.
Modbus timing
Created Date: October 29,2003
Created By: Michel
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I'm using a DL205 as a slave on a PC running a Labview application. I use Modbus/RS485 to communicate on port2. When I write to the PLC many commands at different addresses sequencially, I have to implement some delay loops between the send commands to make sure that the PLC has time to read everything. Without delays, the PLC looses some data. Is there a more elegant way of controlling the writing to the PLC since there are no handshaking lines? Thanks.
Created Date: January 22,2004
Created by: Mike McClanahan
I don't know about labview but some programs have an adjustable write delay in the communications parameters to allow for slower data links (such as repeated radio transmisstions) to have a chance to complete. Modbus expected you to handle communtions delays in your program.
Created Date: October 29,2003
Created by: Michel
I'm using a DL205 as a slave on a PC running a Labview application.
I use Modbus/RS485 to communicate on port2.
When I write to the PLC many commands at different addresses sequencially, I have to implement some delay loops between the send commands to make sure that the PLC has time to read everything. Without delays, the PLC looses some data.
Is there a more elegant way of controlling the writing to the PLC since there are no handshaking lines?
Thanks.