Gas Governor Meter Pulse Transmitter Modules

Dresser meters are widely used and typically include a pulse transmitter mounted to the side of the mechanical index. The index is driven by impellers that rotate with the gas flow. A magnet within the index passes a reed switch inside the transmitter to generate a pulse.

• Reed switch connects to pins 2 and 3 of the RJ11 plug (the two centre contacts).
• Pulses represent volume counts as configured by the meter and transmitter.

Some Dresser transmitters use a 4-pin circular "EGG" connector. In this arrangement, the reed switch connects to pins 3 and 4. With the red mark at 12 o'clock, both contact pins are on the left-hand side.

Elster diaphragm meters have their own pulse transmitter with two outputs: the main volume pulse and a tamper alarm. Both use the same RJ11 plug as Dresser meters, and Elster modules include a printed diagram indicating pin assignments.

• Two outputs: volume pulse and tamper.
• Confirm pulse type, scaling, and connector pinout on site.

Most turbine meters for natural gas use a 6-pin circular connector for pulse acquisition. FMG and Itron are the most common brands. Although they share the same plug type, their pulse modules have different wiring. Both manufacturers include wiring diagrams on the mechanical index.

• Itron: pins 1-2 and 5-6 for pulses; pins 3-4 for tamper.
• FMG: pairs 1-4 and 2-5 for pulses; pins 3-6 for tamper.

Typical low-frequency (LF) wiring on Itron turbine meter modules.

• Pulses on pins 1-2 and 5-6
• Tamper on pins 3-4

Typical low-frequency (LF) wiring on FMG turbine meter modules.

• Pulses on pairs 1-4 and 2-5
• Tamper on pins 3-6