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INTRODUCTION
The Model 1250B Programmable Position Monitor is a highly advanced solid-state
instrument, which measures the absolute position of a synchro transmitter. It provides both a
user definable visual panel indication, and optional analog and digital signal outputs suitable
for a variety of monitoring and control applications.
The 1250B may be programmed to perform mathematical scaling and offsetting of the
rotational position of the synchro transmitter. A special feature of the 1250B is its capability
to monitor up to 100 definable position segments. This is particularly suited to monitoring
power transformer load tap changer position, where the desired readout is in whole tap
numbers, and small discrepancies in position are masked. The display and all outputs follow
a “stair step” function defined in the program when in this mode.
Another powerful feature of the 1250B is its ability to convert rotational position to a
non-linear indication. A conversion table containing up to 100 data point pairs may be
programmed. The 1250B will take a position reading, refer to the conversion table, and
display the converted value. All outputs are driven from the displayed value. This feature
makes the 1250B perfectly suited for applications like hydro dam gate position monitoring, in
which a cable or tape winds onto a spool and the circumference grows with each revolution.
The 1250B may be wired in parallel with existing synchro
transmitter/receiver pairs or
wired directly to the synchro transmitter. Additional 1250Bs may be wired to the same
transmitter without compromising the accuracy or reliability of the system.
1.0 INSTALLATION
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The Model 1250B is designed for use in any 50/60 Hz, five-wire synchro system
compatible with electrical specifications given in Section 6.0 (Specifications). These
devices include CX, TX, CDX, and TDX function synchros, as well as Self-
Synchronous Indicator devices.
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The panel-mount case is designed to snap-fit into a
standard 1/8
DIN rectangular
cut-out of 44mm (1.73 in.) by 92mm (3.62 in.)
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Wiring is done to the rear of the case. #16 AWG (min.) type THHN, THWN, TFFN,
or equivalent wire is recommended for the five AC synchro lines. #20 AWG (min.)
shielded twisted pair wire is recommended for analog output wiring. Use appropriate
spade lugs (provided) when connecting to the case terminals.
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Contact INCON Technical Service (207-571-1202) for application assistance if the
synchro transmitter and the 1250B monitor are separated by a wire run of more than
1200 feet.