ENMET CD-1300-ST - Manual (Page 7)

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Sensor / Transmitter ENMET Corporation
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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, a particular 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:
1. 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’.
2. 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.
3. 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.
4. 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.
5. Remove the shorting block from JP4 to save the value; the unit will reset itself.
6. 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.
7. 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.
8. 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.