Emerson Daniel PT, Инструкция по установке и обслуживанию

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4 Turbine meter instrumentation
4.1 Connection of the Turbine Meter to the
Readout
4.1.1 Pickup Coil
The pickup coil output is an electrical signal of varying amplitude. In most cases a Daniel
preamplifier is mounted on the turbine meter to amplify this signal. A two conductor
shielded cable is used to connect the pickup coil to the pre-amplifier, with the shield
grounded at one end. This shields the signal from electromagnetic interference.
The amplified output is a high level signal and can be transmitted for longer distances. All
Daniel electronic instruments which operate with the turbine meters also provide filtering
of the received amplified signal, and schmitt trigger circuits to eliminate the possibility of
noise interference.
Figure 4-1: Turbine meter pre-amplifier and signals
4.1.2 Pre-amplifier
The Universal Preamplifier (Preamp) converts the low level signal from a turbine meter
inductive pickup to high level pulses. It is distinguished by the following features:
• Tailored Frequency Response:
The sensitivity of the Preamp rolls off as frequency increases, matching the
characteristic output of a turbine meter with inductive pickup. High sensitivity at low
Installation and maintenance instructions Turbine meter instrumentation
3-9008-011 October 2019
Installation and maintenance instructions 33