Sentry Industries 5000 User Manual

 

 

7.4  HYDROGEN SULFIDE MODULE (5100-01) 

7.4.1  DESCRIPTION 

The Hydrogen Sulfide Sensor Module includes the 
sensor and electronic  assembly installed in an 
explosion proof housing.  The sensor screws into 
one hub of the enclosure and plugs into the bottom 
electronics card via a six pin connector.  Cabling 
to the controller connects to a three pin spring 
loaded terminal strip.  

When a sensor is changed it is important that the 
factors for the new sensor are keyed into the 
controller and that a 24 hour stabilization period 
elapses prior to voltage adjustments and 
calibration.   The three factors, each three digits 
are written on the sensor connector label. 

7.4.2  TROUBLE ANALYSIS 

Electrical adjustment, or replacement of the sensor 
will be necessary under the following conditions: 

• 

Controller displays the error messages:  

 

• 

False readings or alarms are received due 
to sensor inaccuracy. 

Warning:  During sensor adjustments the concentration 
reading on the controller will be inaccurate and alarm 
level concentrations may be displayed.  If false activation 
of the alarm relays will cause a problem disconnect the 
relay wiring prior to adjustment or turn the module off 
using the 

mode. 

Prior to reading voltages and making adjustments perform 
a visual inspection to confirm that there are no physical 
problems such as water in the electronics enclosure, 
wiring damage or corrosion. 

Use  Figure  7-5 to locate test points during the following 
procedures. 

Comparing to the 

 (ground) test point measure the 

 (heater voltage) and the 

 

(heater current) values in VDC.  Calculate the power by 
the formula: 

.  The correct value is 400Mw +/- 5 Mw. (Note 

that this calculation is performed by the controller and 
displayed using diagnostic code 0004.) See Table 7-4 for 
corresponding voltage and current settings. 

Adjust the heater power using 

 potentiometer, 

turn clockwise to decrease, counter-clockwise to increase 
the power. Make the adjustments 1/4 turn at a time and 
wait for the values to stabilize before making successive 
adjustments.  

Compare ground to 

 to read the module 

voltage.  The beginning (no gas) value must be above 1.2 
VDC and can be up to 7.5 VDC.  If the no gas voltage is 
lower than 1.2 VDC adjust using 

 

potentiometer.