adccommunitymod (AutomationDirect) asked a question.
Created Date: November 24,2008
Created By: bartb102
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I have a DL450 talking Modbus out port 1 to 4 devices. 3 of them work fine. Fourth is a data logger that doesn't always want to communicate on the first try. The data logger is RS232 so I have a FA-ISOCON converter between it and the RS485 network. The 3 functioning devices are poled every 6 seconds. I'm using NETRX & NETWX instructions. Reading holding registers 40001 through 40006 succeeds 99.999% of the time. Reading registers 40110 & 40111 succeeds 95%. Writing registers 40100 thru 40108 never turns on the success bit, but when I read the registers back, they contain the correct data. Datalogger is fussy, once it starts a measurment process (every 5 minutes) it ignores the Modbus port until it is done. I have the PLC synchronized with the datalogger so I don't begin my update process until the measurment process should be complete, and cancel if the update is not complete in time. Unfortunately the DL450 doesn't return the Modbus error number.
Created Date: November 24,2008
Created by: bartb102
I have a DL450 talking Modbus out port 1 to 4 devices. 3 of them work fine. Fourth is a data logger that doesn't always want to communicate on the first try. The data logger is RS232 so I have a FA-ISOCON converter between it and the RS485 network. The 3 functioning devices are poled every 6 seconds.
I'm using NETRX & NETWX instructions. Reading holding registers 40001 through 40006 succeeds 99.999% of the time. Reading registers 40110 & 40111 succeeds 95%. Writing registers 40100 thru 40108 never turns on the success bit, but when I read the registers back, they contain the correct data.
Datalogger is fussy, once it starts a measurment process (every 5 minutes) it ignores the Modbus port until it is done. I have the PLC synchronized with the datalogger so I don't begin my update process until the measurment process should be complete, and cancel if the update is not complete in time.
Unfortunately the DL450 doesn't return the Modbus error number.