GE 9030 Serial Comms - Basic Question

[keithkyll]

This is my first time using RS232 with GE.
Module is CMM311. Device is RS232, DCE, 2400,8,1,none.
It's a controller that reads vacuum. The vacuum scale is in Torr. 760 Torr is atmosphere - anything below 1 Torr or so would bottom out a standard vacuum gauge. High vacuum is much lower than 1 Torr. To make it simple, the entire range is represented exponentially. Range is 760 to 1.0x10-9 Torr.

Command to read gauge 1: "=RV1"
Response at low vacuum: "1.0-04"
Response at High Vacuum: "1.0-09"
The range for RV1 and RV2 will always be negative.

RV3 through RV6 will be both:
Command to read gauge 3: "=RV3"
Response at atmosphere: "7.6+02"
Response at low Vacuum: "1.0-03"

Questions:
Do I use CCM on port 1 for the format?
How do I convert the ASCII characters returned into a real number so I can compare the reading to a setpoint?

Keith

 

[Steve Bailey]

The CMM311 is limited to SNP, SSM, or RTU protocols. It can't do what you want.

You can do it through one of the serial ports on a CPU352 or CPU363 configured for Serial I/O protocol. You could also do it with a PCM301 module running a Megabasic application.

 

[RussB]

The CMM311 is limited to SNP, SSM, or RTU protocols.

Should read "The CMM311 is limited to SNP, CCM, or RTU slave protocols."
If your HMI has the capability you may be able to run a script in it and communicate to the sensor.

 

[keithkyll]

I ordered a Horner Electric HE693ASC900. Converting the readings to whole numbers will be a breeze in BASIC. I'll still need to convert back for display on the HMI, but that shouldn't be a problem.

Thank you very much for the help.

Keith