Owner's manual

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FIGURE 1. Complete block diagram of the OM2-163 Bridgesensor
OM2-163 Block Diagram
Features
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Pin for Pin Replacement for Model OM2-165
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Compact, complete and convenient to use
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Easy access to all trim adjustments
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Simplifies Single and Half Bridge Applications
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On card Bridge Balance Trimpot eliminates
additional wiring for Three Wire applications
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Changing Bridge supply voltage is easy using
on board trimpot with adjustment range from
+4 to +10 VDC
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Bridge supply lead resistance effects can be
ignored with built-in remote sensing
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Filter frequency can be changed with the flick
of a DIP switch
Description
The OMEGA OM2-163 Bridgesensor is a complete signal
conditioning system on a card designed expressly for single
half, or full bridge transducers. The OM2-163 consists of a
high performance instrumentation amplifier, a user adjustable
active filter, high stability bridge supply and all of the required
circuitry, trimpots, etc., so that only point to point wiring need
be made to the inputs, outputs and power to have a complete
signal conditioning system up and running.
The mounting kit provides coarse and fine gain adjustment
trimpots along with input and output offset adjustments, DIP
switches for setting the bridge supply output and active low
pass filter cutoff frequency. Provisions are also provided to
mount a quarter bridge completion resistor and a calibration
resistor which can be wired to an external CAL switch. Two
close tracking 1/2 bridge completion resistors are also included.
Application of the OM2-163 is easy by following the detailed
applications information that is included with this data sheet
and full engineering specifications allow easy and complete
worst case analysis.
OM2-163 vs OM2-165
The Model OM2-163 is a pin compatible replacement for the
Model OM2-165 which is no longer available. The one major
difference is that the OM2-163 does not have a reference
voltage on pin J. Pin J is connected to COM, pins B and 2. The
OM2-163 also has a high frequency input filter to reduce EMI.
This filter has a high frequency cutoff above 200KHz which is
well above the requirements of weighing systems. See
figure 3 OM2-163 INPUT AMP RESPONSE. The output of the
A
B
C
D
E
F
H
J
K
L
M
N
P
R
S
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
J2
+15V
+SENSE
COM
KEY
15V
+EXCITATION
SENSE
NC
OUTPUT
OFFSET
INPUT
+INPUT
FILTER OUT
AMP OUT
1/2 BRIDGE
COMPLETION
BRIDGE
BALANCE
CALIBRATION
SWITCH
COM
NC
NC
NC
J1
TP1
ST3 ST4
1/4 BRIDGE
COMPLETION
RESISTOR
ST1 ST2
CALIBRATION
RESISTOR
J3
J4
+EXCITATION
+SENSE
SENSE
EXCITATION
BRIDGE
EXCITATION
SUPPLY
SW-1
RP2 BRIDGE SUPPLY
ADJUST
REMOVE J1 TO ADJUST OUTPUT
OFFSET, RP1
TP4
TP3
FILTER OUT
J5
RP1
OUTPUT
OFFSET
RX1
RX2
27K
RP3 INPUT OFFSET
X2 GAIN FILTER AMPLIFIER
100
RG

+
RP4
R6
196
FINE
GAIN
RP5
COARSE
1K
20
10K
10K
+SENSE
R18
56.2K
SENSE
RP6
BRIDGE
BALANCE
TP2
AMP OUT
SW2
SW4
CX2
.22µF
.022µF
.22µF
.022µF
CX1
SW3
SW5
instrumentation amplifier, pin P, is not inverted with respect to
the Filter Output as it was in the OM2-165. The OUTPUT
OFFSET pot, RP1, is disabled by a jumper, J5, which must be
removed to use RP1. The external OUTPUT OFFSET input,
pin K, is always active.
Applications using the OM2-165 can use the OM2-163 simply
by inserting the board and making the typical zero and span
adjustments. No wiring changes should be required.