RS Technologies Division of PCB Load & Torque, Inc.
Toll-Free in USA 888-684-2894
716-684-0001
www.pcbloadtorque.com
HAND TORQUE-ANGLE WRENCH OPERATION MANUAL
4
2.0 SAFETY INFORMATION
Applied loads must be limited to 100% of the rated capacity.
Application of loads exceeding rated capacity can lead to
damage of the hand torque wrench and potential injury to the
operator. Therefore, always use care in applying torque to
fasteners being audited or tightened failure. Operators should
always observe standard shop safety requirements, such as
wearing steel-toed shoes, safety glasses, etc.
3.0 MECHANICAL INSTALLATION
Mechanical installation consists of attaching the proper sized
socket or drive fitting to the hand torque wrench. This socket
or drive will be lined up with the fastener being tightened.
Typical applications will be for auditing the residual torque in
a previously assembled fastener, or for final tightening of a
critical fastener.
4.0 ELECTRICAL INSTALLATION
The hand torque wrench is connected to a data collector or
signal conditioner via the 10-pin PT receptacle located on the
end of the handle. Cable assemblies for RS Technologies and
other instruments are available through RS Technologies
Division of PCB Load & Torque, Inc.
Connect one end of the cable to the wrench connector and the
other end to the data collector signal conditioner. Make sure to
completely tighten the cable connector to the wrench.
5.0 POLARITY
Clockwise torque on hand torque wrenches produces a
positive-going
signal
output. Counterclockwise torque
produces a negative-going signal output. Most data collectors
provide a CW/CCW adjustment to ensure accurate readings.
6.0 SHUNT CALIBRATION
Shunt calibration is the known, electrical unbalancing of a
strain gage bridge by means of a fixed resistor that is placed,
or “shunted”, across one leg of the bridge. The Wheatstone
Bridge utilized by RS Technologies hand torque wrenches is
typically calibrated using the shunt calibration technique.
Shunt calibration is a practical method for providing field
calibration of data collectors and strain gage transducers such
as hand torque wrenches. This provides assurance of obtaining
accurate readings without having to apply known, traceable,
physical input loads to the wrench, which may be impractical
in an assembly line or out in the field.
Shunt calibration simulates the mechanical input to a
transducer by unbalancing the bridge with a fixed resistor
placed across, or in parallel with, one leg of the bridge. For
clockwise shunt calibration, or +CAL, the shunt resistor (R
CAL
)
is shunted across the +Excitation (A) and +Signal (C) leg of
the bridge. For counterclockwise shunt calibration, or –CAL,
the shunt resistor (R
CAL
) is shunted across the -Excitation (BD)
and +Signal (C) leg of the bridge. See Figure 1 for shunt
resistor locations in the Wheatstone Bridge circuit.
Shunt calibration is accepted throughout the industry as a
means of periodic calibration of a data collector and a hand
torque wrench between calibrations of known, applied,
traceable, mechanical input values. Consequently, most all
strain gage transducer manufacturers collect and supply shunt
calibration data, along with a shunt calibration resistor, as a
standard feature.
The hand torque wrench provided by RS Technologies
Division of PCB
Load & Torque Inc.
comes with a calibration
certificate. On the first page of this certificate you will find a
calibration value in engineering units that is associated with a
particular resistor. This resistor can be installed on the data
collector and used when matching up the instrument to the
wrench. Follow the instructions provided with the data
collector for complete details on shunt calibration procedures.
6.1 ANGLE CALIBRATION
If the torque-angle wrench will be used with an RS
Technologies Model 920, 960, or 962 meter with auto ID
enabled, the torque wrench parameters will be auto detected. If
not using the torque-angle wrench with auto ID enabled, or if
using a non-RS Technologies meter, manually enter the
‘Counts/Revolution’ value stated on the calibration certificate
into the transducer’s definition before calibrating to meter to
the wrench.
