ABB Symphony Harmony Series Instruction page 42

Introduction
Overview
Intended User
WBPEEUI260047A0
The NTHS03 Hydraulic Servo Termination Unit is a Harmony
rack I/O device that is part of the Symphony Enterprise Man-
agement and Control System. It provides a signal path
between an IMHSS03 Hydraulic Servo Module and a hydraulic
servo valve, I/H converter, or linear variable differential trans-
former. The IMHSS03 module is a position control module
through which a rack controller can control a hydraulic actua-
tor via a servo valve. By regulating the current to the servo
valve, it initiates a change in actuator position. A linear vari-
able differential transformer (LVDT) provides actuator feed-
back to the IMHSS03 module via the NTHS03 termination
unit. Typical uses for this hardware are positioning steam tur-
bine throttle and control valves, gas turbine fuel valves, inlet
guide vanes, and nozzle angle.
Figure 1-1 shows the Harmony rack I/O architecture. A Har-
mony area controller and the Harmony rack controllers can
use the rack I/O module and termination units for I/O
interface.
Personnel installing, operating, or maintaining the NTHS03
termination unit should read this instruction before perform-
ing any installation, operation, or maintenance procedures.
Installation requires an engineer or technician with experience
handling electronic circuitry. Those working with the NTHS03
termination unit should have experience working with and
know the precautions to take around AC/DC power. A knowl-
edge of the Symphony system, electronic principles, analog
control tuning experience, turbine startup, plant operating
procedures, hydraulic actuators, servo valves, and I/H con-
verters is also required.
Section 1
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