Teledyne t320u Manuale Utente
Teledyne API – Model T300/T300M CO Analyzer
Troubleshooting and Service
283
12.5.7.6. PRESSURE/FLOW SENSOR ASSEMBLY
The pressure/flow sensor PCA, located on the top of the absorption bench, can be
checked with a voltmeter using the following procedure which, assumes that the wiring
is intact, and that the motherboard and the power supplies are operating properly:
checked with a voltmeter using the following procedure which, assumes that the wiring
is intact, and that the motherboard and the power supplies are operating properly:
1. For Pressure related problems:
Measure the voltage across C1 - it should be 5 ± 0.25 VDC.
If not, then the board is bad.
Measure the voltage across TP4 and TP1.
With the sample pump disabled it should be 4500 mV ±250 mV.
With the pump energized it should be approximately 200 mV less.
With the sample pump disabled it should be 4500 mV ±250 mV.
With the pump energized it should be approximately 200 mV less.
If the voltage is incorrect, then S1, the pressure transducer is bad, the board is bad, or
there is a pneumatic failure preventing the pressure transducer from sensing the
absorption cell pressure properly.
there is a pneumatic failure preventing the pressure transducer from sensing the
absorption cell pressure properly.
2. For flow related problems:
Measure the voltage across TP2 and TP1 - it should be 10 ±0.25 VDC.
If not, then the board is bad.
Measure the voltage across TP3 and TP1:
With proper flow (800 sccm at the sample inlet) this should be approximately
With proper flow (800 sccm at the sample inlet) this should be approximately
4.5V (this voltage will vary with altitude).
With flow stopped (sample inlet blocked) the voltage should be approximately
1V.
If the voltage is incorrect, the flow sensor is bad, the board is bad, or there is a leak
upstream of the sensor.
upstream of the sensor.
06864B DCN6314