Sentry Industries 5000 User Manual

 

 

1.  Confirm that system power has been 

removed. 

2.  Remove the transmitter electronics board 

from the main housing and unplug the 
sensor harness from the transmitter 
electronics. 

3.  Unscrew the sensor housing from the 

bottom of the enclosure 

4.  Hold the sensor assembly so that the 

harness faces down and the sensor faces 
up.  Unscrew and remove the round 
section of the housing from the hex 
section.  Be careful not to lose the spacer 
washer which will be sitting on top of the 
exposed sensor. 

5.  Carefully pull the old sensor straight up 

from the socket. 

6.  Orient the new sensor so that the sensor 

pin labeled “

 faces the socket labeled 

 which is on the far side of the board 

from the vertical reed switch.  The reed 
switch will slide into a hole on the side of 
the new sensor.  Press the new sensor’s 
pins into the three sockets. 

7.  Carefully replace the cover on the sensor 

assembly including the spacer washer. 

8.  Install the sensor assembly into the enclosure and 

tighten firmly. 

9.  Reconnect the sensor harness to the transmitter, 

install the transmitter into the housing and restore 
power. 

10.  Allow one hour for the sensor to stabilize prior to 

recalibration. 

11.  Recalibrate the sensor module. 

The following procedure is to be used when, during 
normal calibration  of a new sensor, the span voltage 
cannot be adjusted to a high enough level. 

1.  Adjust the span potentiometer so that it is 

approximately mid range.  (Twenty turns 
clockwise and tens turns counter-clockwise). 

2.  Remove system power and remove both the 

transmitter and the sensor assembly from the 
enclosure.  Remove the sensor assembly cover so 
that the sensor is visible. 

3.  Plug the sensor harness into the transmitter 

assembly and check that no components are 
touching the enclosure.  Restore power and allow 

a minimum of 30 minutes for stabilization before 
adjustment. 

4.  Connect a DVM across TP10 and GT1 on the 

transmitter assembly.  Figure 7-10 

5.  Locate the gain potentiometer which is on the 

sensor electronics directly behind one of the holes 
in the sensor body.  The potentiometer is 
accessible by inserting a jewelers screwdriver 
through the hole in the sensor. 

6.  Determine the correct value to be read at TP10 

based on the following formula: 

V

TP10

= 2(C/R) , where C = concentration of span gas, 

and R = range of detection (100 PPM). 

7.  Apply span gas.  Adjust the gain potentiometer 

until TP10 = correct value as described above.  
To increase voltage at TP10 turn the gain 
potentiometer counter clockwise. 

8.  Remove system power and re-install the sensor 

and transmitter in the enclosure.  Restore power 
and calibrate.