T
WO
-P
OINT
(D
EADWEIGHT
) C
ALIBRATION
PLEASE NOTE:
AS MENTIONED ABOVE, THIS CALIBRATION TECHNIQUE GENERAL-
LY APPLIES TO A MODEL 10A73-4 CHANNEL ONLY WHEN THAT CHANNEL IS CON-
NECTED TO A FULL-BRIDGE STRAIN GAGE TRANSDUCER, AS ARE THE FOUR
CHANNELS SHOWN IN FIG. 4.
Using the standard
ZERO (ZRO)
and
FORCE (FRC)
commands, this conventional
“zero and span” method can be applied to a “full-bridge” 10A73-4 channel if the full-
scale “mV/V” rating of the channel’s strain gage transducer is unknown, or if the final
measurement accuracy provided by CALCULATED CALIBRATION does not meet the
requirements of the measurement application. The mainframe’s
EEPROM Write Pro-
tect Switch
must be ON for the
ZRO
and
FRC
commands to be effective. See Manu-
al Section 1.G.5 for a general discussion of this calibration technique.
S
IMULATED
(S
HUNT
) C
ALIBRATION
This is a convenient “shunt resistor” method, where the second (“span”) input is not
produced by loading the source transducer, but by “simulating” a particular up-scale
value of mechanical input. This known EQUIVALENT INPUT then serves to determine
the SCALING FACTOR for the channel.*
For a 10A73-4 data channel, the equivalent input is produced by shunting a resistor of
known magnitude across one arm of the strain gage bridge, thereby simulating a
known value of input for either a positive or negative up-scale reading. If the transduc-
er manufacturer has supplied the exact value of the transducer’s equivalent input, it
can be used as a reference point for calibrating the channel.
Equivalent input can be approximated from a knowledge of the Shunt Calibration
Resistance (R), the transducer’s Bridge Resistance (B), and the transducer’s Full-
Scale Sensitivity (K, in mV/V full scale). To determine the EQUIVALENT INPUT (X) as
an approximate percentage of full-scale output, you may use the following equation:
X = 25000B / K(R + 0.5B) %
Since the equivalent input is here expressed as a percentage of full-scale output, you
must multiply it by the rated full-scale capacity of the transducer, in order to determine
the actual input simulated by the shunt.
IMPORTANT:
FOR A 10A73-4 CHANNEL WITH BRIDGE COMPLETION—BY MEANS
EITHER OF A SYSTEM BRIDGE COMPLETION CONNECTOR OR THE MODEL
10CJB-4—THE EQUIVALENT INPUT SHOULD BE EXPRESSED IN MICROSTRAIN
(MICROINCHES/INCH).
10A73-4.
10
S
ETUP AND
/
OR
O
PERATING
C
ONSIDERATIONS
10A73-4
Q
UAD
1/2 & 1/4 B
RIDGE
DC S
TRAIN
G
AGE
C
ARD
* Shunt calibration is easier though generally less accurate than two-point (deadweight) calibra-
tion. It is good for an accuracy of about 0.2% (depending, of course, on the accuracy of the
specified equivalent input, and on the resistor/bridge tolerance and temperature).
Rear I/O Connector
Side 2
Chn.1 (#R5)
Terminal post for connection of shunt resistor
Chn.2 (#R6)
Chn.3 (#R7)
Chn.4 (#R8)
Fig. 7 Model
10A73-4
Shunt
Calibration
Resistors
Summary of Contents for System 10
Page 31: ...GETTING YOUR SYSTEM 10 ON THE AIR SB 2 FOR A SIZED MAINFRAMES...
Page 67: ...GETTING YOUR SYSTEM 10 ON THE AIR SB 2 FOR B SIZED MAINFRAMES...
Page 122: ...THIS PAGE INTENTIONALLY BLANK...
Page 134: ...1 12 THIS PAGE INTENTIONALLY BLANK...
Page 142: ...1 20 THIS PAGE INTENTIONALLY BLANK...
Page 150: ...1 28 THIS PAGE INTENTIONALLY BLANK...
Page 174: ...10A16 4C 6 THIS PAGE INTENTIONALLY BLANK 10A16 4C QUAD PLATINUM RTD CARD...
Page 186: ...10A18 4C 8 THIS PAGE INTENTIONALLY BLANK 10A18 4C QUAD PLATINUM LINEAR RTD CARD...
Page 212: ...10A40 8 THIS PAGE INTENTIONALLY BLANK 10A40 FREQUENCY CARD...
Page 224: ...10A43 4 THIS PAGE INTENTIONALLY BLANK 10A43 DWELL ANGLE CARD...
Page 234: ...10A48 6 THIS PAGE INTENTIONALLY BLANK 10A48 FLOW CARD...
Page 242: ...10A61 2 4 THIS PAGE INTENTIONALLY BLANK 10A61 2 DUAL 4 20 MA CARD...
Page 252: ...10A63 2 6 THIS PAGE INTENTIONALLY BLANK 10A63 2 DUAL DC VOLTAGE CARD...
Page 270: ...10A69 4 6 THIS PAGE INTENTIONALLY BLANK 10A69 4 QUAD AC RMS CARD...
Page 276: ...10A70 2 6 THIS PAGE INTENTIONALLY BLANK 10A70 2 DUAL DC STRAIN GAGE CARD...
Page 288: ...10A72 2C 12 THIS PAGE INTENTIONALLY BLANK 10A72 2C ENHANCED DUAL DC STRAIN GAGE CARD...
Page 320: ...10A74 4C 18 THIS PAGE INTENTIONALLY BLANK 10A74 4C QUAD DC STRAIN GAGE TRACK HOLD CARD...
Page 342: ...10A96 8 THIS PAGE INTENTIONALLY BLANK 10A96 AMPLIFIED ACCELEROMETER VIBRATION CARD...
Page 362: ...AA30 4 12 THIS PAGE INTENTIONALLY BLANK AA30 4 QUAD LVDT CARD...
Page 374: ...AA41 2 4 12 THIS PAGE INTENTIONALLY BLANK AA41 2 AA41 4 DUAL QUAD FREQUENCY CARD...
Page 390: ...AA72 2 4 16 THIS PAGE INTENTIONALLY BLANK AA72 2 AA72 4 DUAL QUAD DC STRAIN GAGE CARD...
Page 394: ...1 32 THIS PAGE INTENTIONALLY BLANK...
Page 404: ...1 42 THIS PAGE INTENTIONALLY BLANK...