Tec Control Board; Figure 6-20. Pmt Cooling System Block Diagram - Teledyne T200 User Manual

The target temperature at which the TEC system keeps the PMT is approximately 8.0ºC.
Arriving at this temperature may take up to 30 minutes after the instrument is turned on.
The actual temperature of the PMT can be viewed in the Dashboard.

TEC CONTROL BOARD

The TEC control PCA is located on the sensor housing assembly, under the slanted shroud,
next to the cooling fins and directly above the cooling fan. Using the amplified PMT
temperature signal from the PMT preamplifier board (see Section 6.5.1), it sets the drive
voltage for the thermoelectric cooler. The warmer the PMT gets, the more current is passed
through the TEC causing it to pump more heat to the heat sink.
A red LED located on the top edge of this circuit board indicates that the control circuit
•
is receiving power.
Four test points are also located at the top of this assembly.
•
• For the definitions and acceptable signal levels of these test points see Section
5.7.9.14.
083730200A DCN7962
Preamp PCA sends
buffered and
TEC PCA sets
amplified thermistor
appropriate
signal to TEC PCA
drive voltage for
cooler
TEC
Control
PCA
Thermo-Electric Cooler
PMT Temperature Sensor
Cooling Fan

Figure 6-20. PMT Cooling System Block Diagram

Teledyne API T200 NO/NO
PMT
Preamp
PCA
outputs temp of
PMT
Cold Block
Heat form PMT is absorbed
by the cold block and
transferred to the heat sink
via the TEC then bled off
into the cool air stream.
/NO Analyzer with NumaView™ Software
2 x
Thermistor
cold block to
preamp PCA
211