I-E96-322A
Preface
The IMHSS03 Hydraulic Servo Module is a valve position con-
trol module used in an INFI 90
®
system to control the speed of
a turbine. It interfaces a servo valve or an I/H converter to an
IMMFP01, IMMFP02 or IMMFP03 Multi-Function Processor
Module. The multi-function processor (MFP) module controls
the position of a steam or gas turbine throttle valve by sending
a position demand to the hydraulic servo (HSS) module. The
HSS module drives its outputs to open or close the throttle
valve to match the position demand. The MFP module uses the
IMFCS01 Frequency Counter Module to measure the turbine
speed. The frequency counter module measures turbine speed
by counting and timing pulses from a magnetic pickup on the
turbine shaft. The MFP module uses this count to calculate
turbine speed and calculate a new demand based on a set
point.
The IMHSS03 module is a compatible replacement of the
IMHSS01 or IMHSS02 module and offers improved perfor-
mance. The IMHSS03 module automatically tunes its demodu-
lator gain, offering a more optimal response.
This instruction provides information and instructions on
IMHSS03 module installation, calibration and tuning, opera-
tion, maintenance and troubleshooting. Anyone installing, cal-
ibrating, tuning or operating the IMHSS03 module should read
and understand this instruction.
® INFI 90 is a registered trademark of Elsag Bailey Process Automation.
