Accessories

Pulse Generator V2.0-Ex

Application 

 The Pulse Generator for RITTER gas meters is a rotary encoder for pulse output. It can be used to transfer the recorded data (quantity of measured gas volume [ltr] ) to an external measuring instrument (PC, transcriber). For use in hazardous environments, the explosion proof version is equipped with an inductive sensor (instead of photo sensor). PTB Approval No.: PTB 99 ATEX 2219 X.

Equipment 

 The Pulse Generator is located within the casing of the counter mechanism of the Gas Meter (behind the dial plate) and it consists of the following components: 

 
•  Sit disk 
 
•  Inductive sensor 
 
•  3-pin ex-proof output socket 
 

Description 

 The measuring drum (with drum-type meters) resp. the measuring unit (with bellow-type meters) is coupled 1:1 to the slit disk via a magnetic coupling. The slits/flags of the slit disk rotate through the U-shaped inductive sensor. Thus, the inductive sensor converts the revolution of the measuring drum into a sequence of pulses. The number of pulses represents the volume of gas which has passed through the Gas Meter, depending on the respective resolution (see table on page 03.12). The frequency of the sequence of pulses is a measure of the rotational speed of the measuring drum and thereby a measure of the flow rate of the gas. 

 For operation of the inductive sensor, an external electric power supply with 5 Volts DC is required. More electrical data are stated on the data sheet 03.13. The output signal is a rectangular pulse, whereby the pulse level (= min./max. voltage of the signal) depends on the user-side circuit, i.e. the value of the used resistors.

Output Socket 

 The pin connection of the 3-pin output socket is shown on page 03.13.

Connection of "Electronic Display Unit" EDU 32 FP (optional accessory) to the Pulse Generator 

 The Pulse Generator can be connected to the optional accessory "Electronic Display Unit" by means of the 3-pin connection cord, which is supplied in conjunction with the Electronic Display Unit. The Electronic Display Unit contains the power supply for the inductive sensor as well as the evaluation circuit/logic which enables the direct readout of the measured volume [ltr] and flow rate [ltr/h]. 

 The measurement results displayed by the Electronic Display Unit can be transmitted to a computer via the standard-type interface RS 232 (refer to chapter 4 "Electronic Display Unit" as well). Additionally, the value of the flow rate can be transmitted to an analog measurement device via the standard-type analog output (0-1 Volt or 4-20 mA).

Use with Drum-type Gas Meters 

 When the Pulse Generator is used with drum-type gas meters for recording the gas flow, it is possible for the respective output voltage curve (line) to be slightly wavy, even when gas flow is constant. This is (unpreventable) caused by the type of construction of the measuring drum: the drum consists of four separate chambers, which are closed and opened in sequence. The previous chamber has to be closed before the next chamber will open. This compulsory measurement produces the high measuring accuracy. However, each closing/opening also causes a small reduction in the rotational speed of the measuring drum. This is barely visible to the eye but is documented precisely by a computer/transcriber. Thus, the slightly wavy output line at constant input flow documents the true flow through the gas meter.

Performance Data

* TG types: Revolution of measuring drum ( = revolution of large Needle of dial plate)
 * BG types: Revolution of large Needle of dial plate

Dimensions of slit disk

Output Socket Pulse Generator (View to the socket)

Subject to alterations