With this optical NAMUR sensor you can test gasmeters without a pulse output.
It is a two-wire sensors designed for use with intrinsically safe switching amplifiers as is used in all RTF test facilities. The sensor comes with a special prepared cable that can be connect to the RTF sensor box. Aim the sensor at the blinker in the counter. As soon as air flows through the gas meter, the telemetry will spin. Each time the blinker passes, a pulse is given.
A red LED on the rear of the sensor lights up whenever the sensor sees the "Puls" condition. A 15-turn slotted brass screw Gain control potentiometer enables precise adjustment of system sensitivity.