Table of Contents
Advertisement
Operational Theory
mistor, which is physically located in the cell block. The thermistor is a
temperature dependent resistance that changes the gain of the amplifier
in proportion to the temperature changes in the block. This change is in-
versely proportional to the change in the cell output due to the same
temperature changes. The result is a signal that is temperature
independent. The output from the second stage amplifier is sent to an
18-bit analog to digital converter controlled by the microprocessor.
The digital concentration signal along with input from the control
panel is processed by the microprocessor, and appropriate control
signals are directed to the display, alarms, and communications port.
The same digital information is also sent to a 12-bit digital to analog
converter that produces the 4-20 mA DC and the 0-1 VDC analog
concentration signal outputs, and the analog range ID outputs.
Signals from the power supply are also monitored, and through the
microprocessor, the system failure alarm is activated if a malfunction is
detected.
Teledyne Analytical Instruments
3000RS-P
16
Advertisement
Table of Contents
