Teledyne 3290 - OEM percent oxygen analyzer - Manual (Page 24)

Operational Theory Model 3290
Teledyne Analytical Instruments 14
The digital concentration signal along with input from the front
panel buttons (KEYBOARD) is processed by the micro-controller, and
appropriate output signals are directed to the display, alarm relays, and
the optional RS-232 output. The same digital information is also sent to
a 12-bit digital to analog converter (DAC) that produces the 0-10 VDC
analog concentration signal and the 0-10 VDC analog range ID output.
A current to voltage converter (E–I CONV) produces the 4-20 mA DC
analog concentration signal.