Edgetech PPM1, Operator'S Manual, Page: 10 / 29

10

Leak check the system after installation.

Purge the sampling system with dry gas after installation.

Do not expose the sensor to excess pressure.

Allow sufficient time for the system to dry out before attempting to take
measurements.
The sensor gas connections are ¼ inch (6.35 mm) compression fittings. See the
sensor mounting hole information in the Appendix of this manual.
If the gas to be measured is not completely clean, you may wish to install an
upstream filter in the system. A sintered stainless steel filter element is
recommended.
4.3 ELECTRICAL WIRING
See Figure 4-1, the electrical wiring diagram. All connections are clearly marked
on the circuit board.
4.3.1 SENSOR CONNECTIONS
The connector end of the Sensor cable is plugged into the Sensor. The other
(wired) end should be routed through the left hand feed-thru fitting at the bottom
of the electronics housing. Two wires are connected to the terminals marked
“SENSOR,” and the shield wire is connected to the terminal marked “CH GND”.
4.3.2 POWER CONNECTIONS
Power is supplied by a user-furnished unregulated DC power supply. Voltage
range may be between 18 and 30 VDC, at 100 mA maximum. Connect the
positive side to +VIN, and the negative side to RTN.
4.3.3 ANALOG OUTPUTS
The 4 to 20 mA Analog Outputs, if used, may be routed through the left-hand
feed-thru fitting. The positive side of Output 1 is connected to the terminal
marked OUT1, and the return to the adjacent terminal marked RTN. Similarly,
Output 2 is connected to OUT2 and RTN.
4.3.4 ALARM RELAYS
The Alarm Relays, if used, may be routed through the right-hand feed-thru fitting.
The contacts are Normally Open. Two alarm wires may be connected to the
terminals marked K1, and two may be connected to the terminals marked K2.
4.3.5 RS-232 SERIAL PORT
The built-in serial port is bi-directional, and includes a Type DB-9 RS-232
connector mounted on the circuit board. Any industry standard RS-232 cable
may be used. It is recommended that the installer wire the connector to one end
of the cable
after routing it through one of the feed-thru fittings mounted to the
bottom of the electronics housing.