DayTronic 3000 series, Instruction Manual

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Daytronic Corporation
The Model 3178 is useful in applications involving transformer coupling to the
strain gage bridge (for example, rotary transformer torque sensors) and in certain
applications that require high sensitivity with optimum
signal-to-noise
characteris-
tics. Carrier amplifiers offer higher sensitivity than dc amplifiers and, since they
respond only to the modulated carrier frequency, they reject certain extraneous
voltages that can cause error in dc systems. These error sources include
ther-
mocouple
or
galvanic
voltages in the cable-connector system,
homopolar
voltages
from rotating machinery,
low-frequency
pickup, and
1/f
noises of various origin.
Consequently, the Model 3178 is an excellent instrument choice when special noise
environment conditions and the need for amplification of low-level signals exist.
Calibration of the 3178 is accomplished by the conventional shunt technique,
using an internally installed calibration resistor. Front-panel CAL buttons provide
for shunt calibration in both the positive and negative realms. An internal symmetry
control provides independent adjustment of negative realm sensitivity for trans-
ducers that do not have symmetrical slope characteristics. Positive-realm calibra-
tion can be remotely checked by means of
Remote Cal
terminals on the instrument
I/O connector.
The 3178 Strain Gage Conditioner is also available in two additional forms. The
Model 3278 contains a Digital Indicator to view the analog output of the conditioner.
The Model 3378 contains a Limit section (in addition to a Digital Indicator) that
provides
High/OK/Low
indications and outputs. The Digital Indicator and Limit
features are standard to all
3000
Instruments and are covered in separate instruction
manuals.
2. INSTALLATION AND CABLING
The following paragraphs provide the instructions for instrument installation
and cabling.
Mounting.
The
3000 Series
Instruments can be operated as bench-top units or
they can be rack- or panel-mounted. Clearance dimensions for a bench-mounted
instrument are given in Figure 2. Panel cut-out dimensions for panel mounting are
also shown in Figure 2. Up to four
3000 Series
Instruments can be mounted in a
19-inch rack using the 1.75-inch high Model 3004 Rack Adaptor. Rack-mounting
dimensions are also given in Figure 2. To panel mount an instrument, proceed as
follows. Refer to Figure 3.
IMPORTANT:
The unit is shipped with two
spacer washers
on the securing screws of the rear-panel I/O
Connector. When
panel-mounting
the unit, you MUST REMOVE THESE WASHERS, so that the printed-
circuit board may move forward about 1/8" during Step (f).
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