Unable to communicate with Visilogic on Modbus Communication

[Ebenezer]

I am trying to communicate with PH Sensor via Modbus, I was able to communicate with the PH Sensor on my laptop using ModScan64 Software using Register Address 8193 as provided by the manufacturer, but I was unable to communicate with it on Vislogic. I connected the Sensor via MJ10-22-CS66. I also set DIP Switch at the back for RS485 yet no communication.

Using ModScan64, I was able to get the parameters for:

8193 for ORP Value

8194 for PH Value

8196 for Temperature

Please how do I write these Register Addresses on Visilogic to poll the data for these parameters from the PH Sensor?

Please find attached the program and the document for the sensor

sup-ph8001-ph-sensor-user-manual.pdf ph 8002 communication.pdf PH Sensor.vlp

[Ausman]

Remember the PLC offset by 1 for register addressing

[Ebenezer]

I have done that, no value. 

[kratmel]

Try 8193 (8192)...

[Ausman]

Also, you're asking for 6 consecutive registers to be read.  The sensor may not like doing such a read.   Given your addresses are 8193, 4 & 6, you could drop your read attempts back to 4 initially and see if that works.  If it doesn't then drop your read length to 2, which should cover 8193 & 4.  If THIS doesn't work, try reading only ONE register. 

Various sensors have different ways of handling sequential and non-sequential numbers.  Quite a few I work with I have to read individual registers to get everything i want out of the unit.  For multiple registers needed, this can be very annoying.  I have one modbus device where everything useful is not sequential, it has internal usage in between,  and it also doesn't like a long sequential read so I can pick registers I want from the total read.   Has to be one by one......

I had a quick look at your vlp, and it all seemed ok apart from my suggestions, but I might have missed something else.

If none of that works, then it is likely that the sensor is not using holding registers, try another type.  Sometimes "standards" are not used.

cheers, Aus