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SC 2000, SC2001, SC3004
VERSION INFO Menu Item
This menu item displays the part number and revision level of the
firmware used by this channels microprocessor.
DISPLAY ADC Menu Item
The options for this menu item are:
•
"OFF" will allow the [VALUE] button to cycle through "TK"
(tracking value), "HI" (peak value) and "LO" (valley value).
This is the recommended option.
•
"ON" will allow the "AD" (percentage of the Analog-to-Digital
converter's full-scale digitizing capability) display source
to be available along with "TK" (tracking value), "HI" (peak
value) and "LO" (valley value) when the [VALUE] button is
pressed on the front panel.
The Analog-to-Digital converter counts are displayed as a per-
centage from -100.00% to 100.00%.
This can be used to establish the transducer's electrical null prior
to mounting. See "Electrical Null and Transducer Mounting" on
page 45 for this procedure.
LINEARIZATION Menu Item
The options for this menu item are:
•
"ON" will allow linearization data obtained from a 3-Point or
5-Point Known Displacement Calibration to affect a channel's
scaled values. This is the recommended option.
•
"OFF" will not allow linearization data to effect the channel's
scaled values.
DISABLE CHANNEL Menu Item
The options for this menu item are:
•
"ON" will bypass the INITIALIZE and RUN modes of the chan-
nel. The track, peak and valley values of the channel are
forced to 0.
•
"OFF" will allow normal operation of the channel.
11.6 Electrical Null and Transducer
Mounting
11.6.1 Overview
The mechanical travel of an LVDT transducer is not the same as
its usable measuring range. All LVDTs exhibit some non-linearity
near the ends of its armature's mechanical travel. To insure that
the LVDT will be used in its linear measuring range, its electri-
cal null point must be determined. This electrical null point is the
armature position which produces the minimal electrical signal
output. After electrical null has been established, the LVDT is
clamped down into final position in its mounting fixture.
As long as the LVDT remains clamped in this position, you do not
need to re-establish the electrical null prior to every calibration.
11.6.2 Procedure
•
Step 1: Use the channel's SETUP menu and set DIAGNOSTICS
-> DISPLAY ADC to "ON". Exit the SETUP menu and re-start
the instrument.
•
Step 2: Display the channel to which the LVDT is connected.
Press and release the [VALUE] button until the "AD" display
source is shown. This is the raw analog-to-digital converter
readings displayed as a percentage of its full-scale (-100%
to +100%).
•
Step 3: Move the LVDT's armature to the position which
displays the lowest value of raw analog-to-digital converter
readings (i.e. a number close to 00.000%. This is the LVDT's
electrical null.
•
Step 4: Firmly clamp down the LVDT's body.
•
Step 5: Move the LVDT's armature to roughly the position
you wish to define as "positive full scale". If the displayed
analog-to-digital converter reading is a negative value, you
must swap the wires connected to the (+)Signal and (-)
Signal pins (labeled as "+SIG" and "-SIG") on the channel's
12-pin connector to make the reading positive.
008-0608-00
Rev. G,
Honeywell Sensing and Control
45
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Troubleshooting
