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Can't get RS232 connection for Center 303 Meter to work
gtemkin
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Posted on 12/13/2017 3:42 PM
Hi

I purchased a NOS CENTER 303 Digital Temperature Meter (2 channel, with serial port for PC connection). I cannot get the PC connection to communicate with Artisan. I've tried connecting with both a Mac and a PC with the same failed results.

I'm not using the CENTER optional communications kit, which I think is just a 3 wire cable and some generic temperature display program. I purchased a 3 wire serial cable on Amazon and I've tried 2 different USB/serial adapters which have FTDI chipsets and have worked fine connecting to other serial devices.

Using a terminal emulation program, and bridging the tip and ring of the cable (loopback mode), I can see that the transmission and receive are working fine with the cable disconnected from the meter.

I've got the Device setup in Artisan as Meter: CENTER 303

and the Serial Port setup as:

Comm Port (for Mac): /dev/cu.usbserial-AH061OI
Comm Port (for PC): COM3

and the remaining parameters are: 9600, 8 N,1 ,1.0

When I press the ON button in Artisan the ET and BT displays show as -1.0 and the status text states "CENTER303temperature(): 0 bytes received but 8 needed".

I verified the 3-wire cable continuity for each line and ground in the cable and also swapped the receive and transmit lines in case that might be the issue.

The CENTER user manual doesn't mention any special startup sequence (do you have to hold down any of the keypad buttons to initiate communications?).

Any help would be appreciated.

Gregg
 
gtemkin
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Posted on 12/18/2017 12:13 AM
Yes I've done all that without any success. I suspect my meter's UART is bad. I've opened the meter up and traced the circuit to a chip that looks like it might be an ASIC device so I think I'm going to have to give it up, possibly just use it as a dumb temperature display. Everything else seems to work.

Thanks,

Gregg
 
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