IST
Page 6
The Interface Solution Experts
Installation
The IST is housed in a universal DIN-style case that
mounts easily on both G-type and Top Hat rails.
Mounting the IST
To mount the IST on Top Hat DIN rail, seat the upper
extrusion on the back panel over the top of the rail and
pivot downward until the housing locks into place.
To mount the unit on G-type rail, seat the extrusion
under the top lip of the rail and pivot downward.
Figure 4 shows the unit’s dimensions.
Electrical Connections
The standard IST has seven active terminals on its
front panel. Units equipped with the TX Option have
eight. Each is labeled according to its intended func-
tion in your application. The terminal blocks are re-
movable, so that units can be replaced without having
to disconnect wiring.
Note:
Some old-style ISTs do not have
removable terminal blocks. Contact your
Moore Industries’ Sales Representative for
information on a Removeable Terminal
Block Option, which makes old unit
connections compatible with the new style
IST.
Calibration Procedure
IST calibration consists of the procedure to adjust unit
Zero and Span pots while receiving input across the
entire rated range. The IST Zero pot provides offset
capability of unit minimum output of ±5% of span. The
unit’s Span pot provides full-scale capability, ±10%,
over the entire input range.
The IST Zero and Span pots are labeled and acces-
sible on the front panel. Each is equipped with a slip
clutch mechanism that prevents damage if turned past
the wiper stop. If unable to sense the wiper stop when
preparing the pot for calibration, simply turn it 15 times
in either direction.With calibration setup complete,
adjust both potentiometers 15 turns counterclockwise,
then 7.5 turns clockwise (approximate mid-scale).
To adjust Zero and Span pots:
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1. Simulate 0% input.
2. Adjust ZERO pot until voltmeter reads
1 V, ±0.1%.
Caution:
To avoid damaging the unit housing, use a
screwdriver with a head not wider than 2.54
mm (0.1 inch) to adjust the Zero and Span
pots.
3. Set input to 100%.
4. Adjust SPAN pot until voltmeter reads
5 V, ±0.1%.
5. Repeat steps 1 through 4 until 0 and
100% readings are stable, ±0.1%.
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