Vaisala GMM220 - Manual (Page 3)

GMM220 _____________________________________________________ CO2 Transmitter Modules
M010115EN-E _______________________________________________________________________ 3
LEDs:
- Normal operation: Led V8 (red) is not lit and Led V9 (green) is blinking.
- Measurement out of range: Led V8 (red) is blinking and Led V9 (green) is blinking,
maximum value is shown. GMM220 returns to normal operation when CO
2
drops
within range.
- Error state: Led V8 (red) is blinking and Led V9 (green) is blinking, no readings. In
error state, check first that the probe is properly connected. In case of constant error,
please contact Vaisala Service Centers.
Serial Interface Protocol
The transmitter is connected to a computer with the optional serial COM adapter
(19040GM). A suitable terminal program such as WINDOWS® Hyper Terminal is
needed for the communication.
Port settings: Baud rate 9600, data bits: 8, stop bits :1, parity: none, flow control: none
Commands
The last character in the GMM220 reply is a prompt >.
Single CO
2
measurement output
DISP option <cr>
Options: 2 = concentration in ppm, 4 = concentration in %
For example:
>DISP 2<cr> the command (bold)
6543.2 <cr><lf> response from the GMM220
> prompt sent by the GMM220
Continuous CO
2
measurement output
MF_MODE option <cr>
Options: 0 = no output, 2 = output concentration in ppm, 4 = output concentration in %
For example:
>MF_MODE 4<cr> the command (bold)
5.625<cr><lf> response from the GMM220
5.625<cr><lf>
5.625<cr><lf>
.
To stop continuous output, give command: MF_MODE 0<cr> or <ctrl+C>