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CD-1300-ST
ENMET
Manual Revision Date – June 15, 2017
P a g e
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6
Manual Part No. – 80003-134
4.0 Field Adjustments
This section describes the features that can be field configured and the procedures to make these changes.
4.1 Analog Output Range Adjustment
This section refers to advanced features of the CD-1300-ST Series.
2000 ppm users need not perform this adjustment.
The
CD-1300-ST series
ships from the factory set for an analog output range of 0 to 2000 ppm. This range can be changed to any
sub-range between 0 and 5000 ppm by changing two parameters:
The
low output threshold
is the concentration at which the analog output will begin to rise. The factory default low output
threshold value is 0.
The
high output threshold
is the concentration at which the analog output reaches its maximum value. The factory default high
output threshold value is 2000.
For example, an application may require the analog output to remain at 0V or 4.0 mA until the gas concentration reaches 500 ppm,
then reach 10V or 20 mA at a concentration of 1000 ppm. In this example the analog output would scale across this 500 ppm sub-
range so that the analog output would be at half scale (5V or 12 mA) at 750 ppm.
To change the analog output range, use the following procedure:
N
OTE
: whether the shorting block at jumper JP5 is covering both pins or only a single pin, then borrow the shorting block and
slide it over the two pins of jumper JP4 (see Figure 2 Section 3.3). The display (if present) will show ‘SEL’.
1.
The display (if present) will show ‘SEL’. Momentarily closing a jumper selects which value to change. If the wrong jumper is
selected simply open JP4 to restart the unit and begin again.
2.
Select the low output threshold by momentarily closing JP1.
If the display is present it will show the current low display threshold. If there is no display the value can be displayed using a
meter connected to the analog output. In this calibration mode, the analog output is 10,000 ppm at full scale (i.e. 10.0 volts or
20.0 mA). If the voltage output is selected, this scaling corresponds to 1 ppm per millivolt or 1000 ppm per volt.
3.
Use the ‘UP’ and ‘DOWN’ buttons to adjust the low output threshold to the desired value. In the example this would be set to
500.
4.
Remove the shorting block from JP4 to save the value; the unit will reset itself.
5.
Reconnect JP4. The display (if present) will show ‘SEL’. Select the high output threshold by momentarily closing JP2. If
present, the display will show the high output threshold. If there is no display use a voltmeter as described in step 3.
6.
Use the ‘UP’ and ‘DOWN’ buttons to adjust the high output threshold to the desired value. In the example this would be set to
1000.
7.
Remove the shorting block from JP4 and restore it to its original position at jumper JP5.
CD-1300-ST series
will reset and its
output will now only change when the gas concentration is within the range selected. Below this range the output remains low,
above this range the output remains high.