Справочник Пользователя для Teledyne gfc 7000ta

 

Teledyne Analytical Instruments 

238 

Dynamic problems (i.e.  problems which only manifest themselves when the analyzer is monitoring 
sample gas) can be the most difficult and time consuming to isolate and resolve.  The following provides 
an itemized list of the most common dynamic problems with recommended troubleshooting checks and 
corrective actions.   

Individual control loops are used to maintain the set point of the absorption bench, filter wheel, and IR 
photo-detector temperatures.  If any of these temperatures are out of range or are poorly controlled, the 
GFC 7000TA will perform poorly.   

The box temperature sensor is mounted to the motherboard and cannot be disconnected to check its 
resistance.  Rather check the BOX TEMP signal using the SIGNAL I/O function under the DIAG Menu 
(See Section 10.1.3).  This parameter will vary with ambient temperature, but at ~30

o

C (6-7° above room 

temperature) the signal should be ~1450 mV.   

The Sample Temperature should closely track the bench temperature.  If it does not, locate the sensor, 
which is located at the midpoint of the optical bench in a brass fitting.  Unplug the connector labeled 
“Sample”, and measure the resistance of the thermistor; at room temperature (25°C) it should be ~30K 
Ohms, at operating temperature, 48°C, it should be ~ 12K Ohms 

 

There are three possible failures that could cause the Bench temperature to be incorrect.   

1.  The heater mounted to the bottom of the Absorption bench is electrically shorted or open.  Check 

the resistance of the two heater elements by measuring between pin 2 and 4 (~76 Ohms), and 
pin 3 and 4 (~330 Ohms), of the white five-pin connector just below the sample temperature 
sensor on the Bench (pin 1 is the pointed end).   

2.  Assuming that the I

2

C bus is working and that there is no other failure with the relay board, the 

solid-state relay (K2) on the relay board may have failed.  Using the BENCH_HEATER parameter 
under the signal I/O function, as described above, turn on and off K2 (D3 on the relay board 
should illuminate as the heater is turned on).  Check the AC voltage present between pin 2 and 4, 
for a 100 or 115 VAC model, and pins 3 and 4, for a 220-240 VAC model.