DayTronic System 10 - 4.c Calibration; Calculated Calibration; Two-Point (Deadweight) Calibration; Simulated (Shunt) Calibration

4.c CALIBRATION
CALCULATED CALIBRATION
You can calibrate a 10A72-2C channel receiving strain-gage input from a Model
10CJB-2 Bridge Completion Card by applying the
MV/V CALIBRATION (MVV) com-
mand as described in Section 3.d, above. Note however that, in this case,
• for “i” (the transducer sensitivity rating), you should enter one of the following full-
scale “mV/V” values, whichever corresponds to the channel’s “type” setting (see
Table 1):
0.75 (for “Type 70”), 1.50 (for “Type 71”), or 3.00 (for “Type 72”).
• for “u” (the nominal full-scale rating), you should enter the full-scale microstrain
range
that corresponds to the selected transducer sensitivity rating, as given in
the following table:
Table 3 Strain Gage Microstrain Ranges (10A72-2C)
Full-Scale Full-Scale
Output (mV/V) Microstrain Range
0.75 u = 3000 / (N • G)
1.50 u = 6000 / (N • G)
3.00 u = 12000 / (N • G)
Here, “N” is the number of active strain-gage arms in the gage configuration.
Thus, for a 1/4-bridge gage, N = 1; for a half-bridge gage, N = 2; and for a full-
bridge gage, N = 4. “G” is the
gage factor of the strain gage, and is normally pro-
vided by the manufacturer.
TWO-POINT (DEADWEIGHT) CALIBRATION
See Section 3.d, above, for the general procedure. Your first calibration point (entered
via the
ZERO (ZRO) command) should be zero. Your second calibration point
(entered via the
FORCE (FRC) command) should be expressed in microstrain
(microinches/inch)
.
SIMULATED (SHUNT) CALIBRATION
See Section 3.d, above, for the general procedure. Your EQUIVALENT INPUT value,
which is entered via the
FORCE (FRC) command—following zeroing of the channel
and switching in of the shunt resistor)—should be expressed in
microstrain (microinch-
es/inch)
.
COARSE ZERO OFFSET
In the event that, during “Two-Point” or “Simulated” calibration of the 10CJB-2 channel,
you are unable to set the desired span via the
FORCE (FRC) command, you can
apply a positive or negative zero offset of approximately 1 mV/V for balance correc-
tion, as follows:
1. Remove the top plate of the 10CJB-2 box and locate the three programming
jumper pads for the channel in question. Labelled “A” for Channel 1 and “B” for
Channel 2, the pads are near the left edge of the 10CJB-2 circuit board.
2. Place a solder drop between the center pad and either the “+” or “–” pad, depend-
ing on the desired offset polarity.
3. Re-enter your
ZRO and FRC values (with or without calibration “shunt”).
OPTIONAL BRIDGE COMPLETION 10A72-2C.11
ENHANCED DUAL DC STRAIN GAGE CARD 10A72-2C