[Simple Serial Read From Load Cell via RS232]

Sorry, I just noticed I should have posted this in the Visilogic forum.

[Simple Serial Read From Load Cell via RS232]

Thank you for your reply. 

 

I'll look into the Message Composer features and tutorials and post how I make out. 

 

I appreciate your help.

[Simple Serial Read From Load Cell via RS232]

Hello,

 

I am new to Unitronics and have just bought a SAMBA unit (SM43-J-R20) with the optional serial port (V100-17-RS4X) and I need some help with getting started.

 

I need to read a load cell via RS232 from the optional port, but am having issues doing so. I've watched some webinars about MODBUS, but am not sure if this is what I need and if it is, what parameters I need to enter. I am using a Cooper Instruments load cell with a digital display. I found the following information in a PDF for the load cell:

 

The output string is in the following format:

<STX> <SIGN> <WEIGHT(7)> <STATUS> <ETX>

 

Where 

• STX: Start of transmission character (ASCII 02).
• ETX: End of transmission character (ASCII 03).
• SIGN: The sign of the weight reading (space for positive, dash (-) for negative).
• WEIGHT(7): A seven character string containing the current weight including the decimal point. If there is no decimal point, then the first character is a space. Leading zero blanking applies.
• STATUS: Provides information on the weight reading. The characters G/N/U/O/M/E represent Gross / Net / Underload / Overload / Motion / Error, respectively.

 

On the PLC Info screen, I have the following information for COM 2:

 

Protocol: MODBUS

RS Type: RS232

Params: 9600 ,8,n,1

Silence: 3650us

the Rx value is constantly incrementing, but under the Monitor screen, there is no value. 

 

Any help would be greatly appreciated as I am new to Unitronics and don't know where to begin. 

 

Thank you for your time.