Detcon DM Transmitter Test Fixture - Manual (Page 7)

Detcon Model DM Transmitter Test Fixture
Page 7 of 8
case, when performing a span cal, you will set SW1 to 50% of scale regardless of what
ppm range is requested by the transmitter during the calibration procedure.
a) Enter the calibration menu by holding the programming magnet stationary over
“PGM 1” for 3 seconds until the display reads “1-ZERO 2-EXIT”, then withdraw
the magnet.
b) From the calibration menu “1-ZERO 2-EXIT” proceed into the span adjust
function by holding the programming magnet stationary over “PGM 1” for 3
seconds until the display reads “APPLY ## PPM” then withdraw the programming
magnet. Note that the CAL LED is illuminated and that the mA Output LED meter
on the test fixture indicates 2.0 mA.
c) Turn SW1 to the “50%” position. The display will change to “AUTOSPAN ##
PPM”. When the sensor signal is stable it will auto span to the requested
concentration and the display will change to “SPAN COMPLETE” for two
seconds and then “REMOVE GAS”. Turn SW1 back to the “0” position. The
display will return to the normal operation menu, “0 PPM ###”.
5 - Check different ranges. Turn SW1 to each position (0, 10, 25, 50, 100) and verify a
matching transmitter display reading (±10%). These position settings are the % of the full
scale range of the transmitter so calculate the proper reading accordingly. For example, If
the range of the transmitter is 0-100 ppm, the reading will equal the number indicated by
the SW1 position. If the range of the transmitter is 0-50 PPM, the reading will equal half
of the number indicated by the SW1 position, and so on. The 100 position will cause an
over-range condition resulting in the display flashing “### PPM ###”. Also verify an
LED mA output reading of 4.0 mA (0), 5.6mA (10), 8.0mA (25), 12.0mA (50), and
20.0mA (100). Return SW1 to the “0” position.
6 - Check zero fault. Turn SW1 to the zero fault position and note the “FLT” LED on the
transmitter illuminates and the display reads “Zero Fault”. Also note that the test fixture
fault LED illuminates and that the mA output LED display indicates a reading of 000.
Return SW2 to the NORMAL position.
7 - Check alarm relay outputs. Turn SW1 clockwise until both alarm LEDs on the
transmitter illuminate. Verify that both alarm LEDs on the test fixture also illuminate.
Return SW1 to the “0” position. If alarms on the transmitter are programmed for latching,
swipe the programming magnet over PGM1 or PGM2 to reset.
8 - RS-485 Out (P3). The DM-550x and DM-624x operate as Modbus slave devices. RS-
485 operation is checked by connecting to an RS-485 Modbus Master device. Reference
the applicable instruction manual for further information.