Meter Head; Block Diagram - RMG TERZ 94 Operating Instructions Manual

Functional Description
The TERZ 94 / 94-S volumeters form a series of uniform construction.
The meters consist of the following principal components:
- meter case
- measuring element (with turbine wheel and sensor) and
- electronic totalizing unit.
An aerodynamic flow straightener (8) fitted into the meter case constricts the
effective cross section of the pipe to form a ring-shaped cross-sectional area
and substantially eliminates turbulences. The velocity of the flowing gas
increases and the gas is directed to the turbine blades.
The turbine wheel (7) is dynamically balanced and mounted with dust-proof
ball bearings (6). A permanent magnet (4) located at the end plate of the
turbine shaft induces the sensor element (3) to give a voltage pulse with each
rotation of the turbine wheel. This pulse is further processed by the electronic
system of the meter head (1).

Meter head

Inside the meter head, the number of pulses is divided by the meter factor
3
(number of pulses per m ) and the result is used to calculate the volume at
measurement conditions. In the main totalizer, the sum of the volume at
measurement conditions which flowed through the meter is formed and you
can read the gas volume which flowed through the meter per time unit on the
flow rate display.
At the HF output, the unchanged signal frequency of the sensor element is
outputted, whereas, for the LF output, this HF frequency can be reduced by
two programmable scaling factors.

Block diagram

TERZ 94
In the display field of the TERZ 94 (not with the TERZ 94-S), a start-stop
totalizer or a resettable totalizer can be optionally displayed. Through the free
sensor input X5, either the volume metering of the start-stop totalizer is
interrupted or the resettable totalizer is reset (depending on the programming
of the TERZ 94).
5
Operating Instructions for the TERZ 91 Electronic Turbine Meter