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Page 6
BX-B31 Data Sheet (BX3)
Input Module Component Glossary
ZERO ADJUST Header
When this header is provided, it works in conjunc-
tion with the ZERO OFFSET RANGE Header, and
expands the ZERO pot’s offset capability into five
equal negative steps or five equal positive steps.
This enables virtually any degree of input signal
offset required to display any desired engineering
unit of measure.
ZERO OFFSET RANGE Header
When provided, this three position header increas-
es the ZERO pot’s capability to offset the input sig-
nal, to ±25% of the digital display span. For exam-
ple a Negative offset enables a 1 to 5V input to
display 0 to full scale. The user can select negative
offset, positive offset, or no offset (ZERO pot dis-
abled for two step non-interactive span and offset
calibration).
SPAN RANGE Header
When this header is provided it works in conjunc-
tion with the SPAN ADJUST Header by splitting its
adjustment range into a Hi and a Lo range. This
has the effect of dividing the adjustment range of
the SPAN pot into ten equal 10% steps across
100% of the input Signal Span.
INPUT RANGE Header
Range values are marked on the PCB.Typically two
to four positions are provided, which are selected
with either a single or multiple jumper clip. When
provided, a custom range position is only functional
when the option has been factory installed.
Input and Output Pins
On most modules Pin 1 is the Signal High input
and Pin 3 is the Signal Low input. Typically Pin 2 is
used for Excitation Voltage output.
24V DC Output Header
On some modules this header enables a 24V DC
25mA (max) Excitation/Auxiliary output to be con-
nected to Pin 2.
Note: I-Series modules with analog calibration and scaling capability
can be interchanged between any compatible meter without recalibra-
tion. However, meters that also have software scaling and calibration
capabilities such as meters in the Leopard and Tiger families or Lynx
Q-Series (Quickset programming), must have their software scaling set
to unity gain.
Basic standard range calibration of direct reading
modules that utilize either Auto Zero or a ZERO pot,
an INPUT RANGE Header and or a SPAN pot.
1 If the module has an INPUT RANGE Header, reposition the jumper
clip to select the desired input signal range.
2. Apply a zero input or short the input pins. The display will auto zero,
or if the module has a ZERO pot, it should be adjusted until the dis-
play reads zero.
3 Apply a known input signal that is at least 20% of the full scale input
range and adjust the SPAN pot until the display reads the exact input
value. The Lynx family of Q meters can accept negative signals also,
and may be scaled for inputs from -50% to +100% of the range
selected on the input signal conditioning module.
Wide range scaling, in engineering units not requir-
ing offsets, with modules that utilize auto-zero or a
ZERO pot, a SPAN RANGE Header and or a SPAN
ADJUST Header.
Input Module Calibration
LO RANGE
HI RANGE
10%
SPAN Pot %
10%
10%
10%
10%
10%
Signal Span %
20%
30%
40%
50%
1
SPAN Adjust
Header position
Span Adjust Header
Span Adjust Header
Span Range Header
2
3
4
5
10%
10%
10%
10%
10%
60%
70%
80%
90%
100%
1
2
3
4
5
< Decrease Span Increase >
1 2
3
4 5
< Decrease Span Increase >
1 2
3
4 5
Equivalent
Circuit
Acts like a
150 Turn
Potentiometer
Low Range
High Range
Input LO
Input HI
HI
LO
< Increase Zero Decrease >
5 4
3
2 1
<
Incre
ase
Ze
ro D
ecre
ase
>
5
4
3
2
1
SPAN
Turn Clockwise to
Increase Reading
To the
Right Rear
HI
LO
24V
Exc
Offset
0
—
+
0
—
+
Custom
200V
20V
2V
ON
OFF
OFF
ON
24V EXC
< Increase Span Decrease >
5 4
3
2 1
< Increase Span Decrease >
5 4
3
2 1
Range
HI
LO
HI
LO
Zero Offset Range Header
Zero Adjust Header
Zero Adjust Header
0 +
–
–20%
ZERO Pot %
–20% –20% –20% –20%
No
Offset
NEGATIVE OFFSET
POSITIVE OFFSET
≈
–75% of display span
Offset Range
+20% +20% +20% +20% +20%
≈
+50% of display span
5
ZERO Adjust
Header position
4
3
2
1
1
2
3
4
5
75 Turn Potentiometer
–
0
Equivalent
Circuit
< Increase Zero Decrease >
5 4
3
2 1
< Decrease Zero Increase >
1 2
3
4 5
75 Turn Potentiometer
+
0
Zero Pot
Disabled
ZERO
Turn Clockwise to
Increase Reading
To the
Left Rear
SPAN Potentiometer (Pot)
If provided, the 15 turn SPAN pot is always on the
right side (as viewed from the rear of the meter).
Typical adjustment is 20% of the input signal range.
15 Turn Potentiometer
≈
+
1000 Counts
≈
–
1000 Counts
–
0
+
20%
SPAN Pot %
20%
20%
20%
20%
20%
Signal Span %
40%
60%
80%
100%
1
SPAN Adjust
Header position
2
3
4
5
< Decrease Span Increase >
1 2
3
4 5
Acts like 75 Turn 1 Megaohm Potentiometer
Input LO
Inp
HI
Equivalent
Circuit
SPAN ADJUST Header
This unique five-position header expands the
adjustment range of the SPAN pot into five equal
20% steps, across 100% of the input Signal Span.
Any input Signal Span can then be precisely scaled
down to provide any required Digital Display span
from 19999 counts to 0001 (one count).
ZERO Potentiometer (Pot)
If provided, the ZERO pot is always to the left of
the SPAN pot (as viewed from the rear of the
meter). Typically it enables the input signal to be
offset ±5% of full scale (-1000 to +1000 counts).
Zero Offset Range Header
0 +
–
No
Offset
NEGATIVE OFFSET
Decreases Digital Reading
POSITIVE OFFSET
Increases Digital Reading
15 Turn Potentiometer
–
0
Equivalent
Circuit
15 Turn Potentiometer
+
0
Zero Pot
Disabled
≈
–
5000 Counts
Offset Range
– 100% of Offset
ZERO Pot%
≈
+
5000 Counts
+ 100% of Offset
WARNING
:
AC and DC input signals and power supply
voltages can be hazardous. Do Not insert, remove or handle
modules with live wires connected to any terminal plugs.
!
