App-14
IM DL850E-01EN
Appendix
Appendix 4 Shunt Calibration of the Strain Module
In shunt calibration, the strain measurement gain is adjusted through the connection of a known resistance (the
resistance for shunt calibration, hereinafter referred to as the shunt resistance) in parallel to the strain gauge.
The strain module (701271 (STRAIN_DSUB)) supports shunt calibration with a built-in shunt-calibration relay
circuit.
To perform shunt calibration, you need a bridgehead that supports shunt calibration (701957 or 701958).
B8023WP
Bridgehead 701957/701958
(with shunt calibration support)
Bridge-
Bridge-
Input+
Input+
Input-
Input-
Sense+
Sense+
Sense-
Sense-
S
Shunt resistor
Shuntcal-
S
Shuntcal-
R
R
R
9
6
8
7
5
2
4
3
1
Shell
Twist
Twist
Twist
Shield
Twist
Bridge-
Input+
Input-
Sense+
Sense-
Suntcal-
Floating Common
Floating
Common
GND
terminal
Case
9
6
8
7
5
2
4
3
1
Shell
Floating
Common
on/off
Shuntcal-
Sense+
+
-
Sense-
Sense+
Sense-
701271
STRAIN_DSUB
AD
Module
All module
signals
are isolated.
Bridge
Power
+
-
Shuntcal
S
Case
1 The GND (floating common) of the module
is connected to the case potential inside the
bridge box.
2 The bridgehead case, the cable shield, and
the measuring instrument case are
connected as measures against noise.
The floating common of the
module is grounded within the
bridgehead.
1
The connector shell is
connected to the case
potential of the bridgehead.
2
The shield is connected to
the bridgehead case and the
measuring instrument case.
2
The connector shell is connected to the
case potential of the measuring
instrument.
2
Measurement instrument
(example: DL850E)
• When correcting the gain on the negative side (normal)
Bridge
voltage
Bridge–
In–
Shunt resistor
(connected to the bridgehead)
120 Ω
In+
120 Ω
120 Ω
Shunt calibration relay circuit
(Built into the strain module.
Turns on and off automatically
when shunt calibration is
executed.)