IM 701240-01E
5-30
Shunt Calibration (Only on the 701271(STRAIN_DSUB))
Shunt calibration is used to correct the gain of strain measurements by inserting a known
resistance (shunt calibration resistance (shunt resistance)) in parallel with the strain
gauge. It is a type of scaling. The Strain Module (701271(STRAIN_DSUB) supports
shunt calibration and has a built-in relay circuit for shunt calibration. To execute shunt
calibration, a bridge head that supports shunt calibration (701957/701958) is needed.
Bridge
voltage
Bridge-
In+
In-
Shunt resistor(Applied
to the bridge head)
Bridge-
In+
In-
Shunt resistor, when correcting
the positive side
120
Ω
120
Ω
120
Ω
• When correcting the gain on the negative side
(normal)
Bridge
voltage
120
Ω
120
Ω
120
Ω
• When correcting the gain on the positive side
(normal)
Shunt calibration relay circuit
(Turns ON/OFF automatically when shunt calibration
that is built into the strain module is executed.)
Shunt calibration relay circuit
(Turns ON/OFF automatically when shunt calibration
that is built into the strain module is executed.)
In addition to the normal shunt calibration (when the shunt calibration relay circuit is ON),
the SL1400 allows the setting of a zero point when the relay circuit is OFF. This function
is effective when the strain value is not 0 after the execution of balancing.
P1:X
If (Shunt Cal) Exec is executed, the input value when the relay circuit is OFF is applied.
P1:Y
Sets the value (usually 0) when the relay circuit is OFF.
P2:X
If (Shunt Cal) Exec is executed when the relay circuit is ON, the input value when the
relay circuit is ON is applied.
P2:Y
Set the strain value corresponding to the shunt resistance when the relay circuit is ON.
Strain
P2:Y
P2:X
Strain input
• Shunt calibration
The strain value corresponding to the shunt
resistor is set to P2:Y of the setup menu.
Current measured
value*
Before execution
After execution
Gain is corrected.
* Automatically obtained when shunt calibration is executed.
For details on shunt calibration, see appendix 10.
Note
•
When executing shunt calibration, select an appropriate range so that the measured values
do not exceed the range when the shunt calibration relay circuit is ON. The SL1400 attempts
shunt calibration within the current specified range.
•
If shunt calibration fails (the measured value exceeds the range, for example), an error
message is displayed. If this happens, change the range and execute shunt calibration again.
5.15 Setting the Strain Measurement