Jetco TTS-1000, Operation Manual

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Checking for accuracy
The Torque Meter and torque transducers are factory calibrated and should be checked on
a regular basis. We recommend that, provided the transducers are used according to this
manual, they be re-certified yearly. Since the frequency of use, among other factors, may
affect the calibration, the user must determine the best calibration interval.
It is important to use the correct arm length since arms that are too short may create
excessive bending loads that are not present during normal operation.
Recommended torque arm lengths:
4” arm (wheel) up to 100 in lb transducers
10” arm (wheel) 250 in.lb to 50 ft. lb.
24”
1 50 ft.lb. to 250 ft.lb.
48” 500 ft. lb. and up
These arm lengths closely represent the length of typical wrenches that will be used on
the transducers. They also allow for usually no more than 150 lbs of weights, which also
represents the “typical” amount of force required to generate the torque with a wrench.
Do not use a 10” arm to calibrate a 250 ft. lb. transducer. This would require 300 lbs of
weights, this is not good for the transducer and is not representative of the typical weight
needed to generate 250 ft.lb. applied by a person. Most conventional torque wrenches are
designed to be long enough to allow no more than 150-175 lb person to generate the force
required to generate the needed torque. Using the above arm lengths will be consistent
with this philosophy.
The accuracy of the meter is such that any incorrect zero caused by out of balance arms,
mis-alignment or sloppy adapters used on the torque arm system may cause a
“perceived”out of tolerance condition. This can happen when you use a female drive
torque arm on a female drive transducer and use a male-male adapter in between with too
much play. It can also happen when you use an adapter to reduce a ½” female drive arm
down to a 3/8” female drive using an off-the-shelf adapter. For this reason you must
always use the proper drive arm with the transducer. If the transducer is a ½” female
drive then you must use a ½” male drive torque arm to eliminate errors.
Even benches that are not flat or deflect during high load calibrations are unacceptable.
In this case the transducer will not be perpendicular with the weights and this mightl
show on the meter (yes the meter is that sensitive), resulting in a possible out of tolerance
condition.
Procedure for checking accuracy
Transducers are calibrated to within .5% (bench type) or 1% extension type
IV +/- .1 at the factory. If you require greater accuracy you can bypass the
smart chip in the transducer and perform a manual calibration on
transducers. This will account for variations in torque arm calibration
systems.
IMPORTANT!
YOU
MUST ALWAYS DO THE FOLLOWING:
MOUNT THE TRANSDUCER SO THE CABLE IS POINTING DOWN.
PUT THE METER IN TRACK MODE.
1. NEVER USE A TORQUE ARM THAT IS NOT BALANCED ABOUT ZERO. A HIGH PRE-
LOAD,OR AN OPPOSITE DIRECTION PRE-LOAD REDUCES ACCURACY AND IS NOT
INDICATIVE OF REAL APPLICATIONS. A SLIGHT PRE-LOAD MAY, HOWEVER, BE
NECESSARY TO TAKE UP DRIVE TOLERANCES IN THE DIRECTION TO BE TESTED. A 1
OR 2 LB HANGER WEIGHT SHOULD BE SUFFICIENT.
2. ALWAYS APPLY FULL SCALE TORQUE, THREE TIMES, WITH WEIGHTS, IN THE
DIRECTION YOU ARE TESTING PRIOR TO RUNNING AN ACCURACY TEST.
3. AFTER STEP 2 ABOVE, WAIT AT LEAST 30 SECONDS OR FOR THE WEIGHT HANGER
TO STABILIZE. SWINGING HANGERS WILL GIVE AN INCORRECT ZERO READING AND
MAY THROW OFF ACCURACY.
4. AFTER STEP 3 ABOVE PRESS THE ZERO BUTTONS ( EVEN IF THE DISPLAY SHOWS
“000.0” ) DO NOT PRESS THEM AGAIN UNTIL YOU START A COMPLETE NEW TEST
CYCLE (STARTING FROM STEP 1 ABOVE).
5. AFTER STEP 4 ABOVE APPLY 10% LOAD, LET THE HANGER STABILIZE AND CHECK
READING. DO NOT REMOVE THE WEIGHTS WHEN FINISHED CHECKING AT THIS
POINT.
6. AFTER STEP 5 ABOVE APPLY ADDITIONAL WEIGHTS TO THE HANGER TO BRING
THE TORQUE TO 50% OF LOAD AND CHECK READING. DO NOT REMOVE THE
WEIGHTS WHEN FINISHED CHECKING AT THIS POINT.
7. AFTER STEP 6 ABOVE APPLY ADDITIONAL WEIGHTS TO THE HANGER TO BRING
THE TORQUE TO 100% OF LOAD AND CHECK READING.
THE MAJORITY OF ACCURACY PROBLEMS OCCUR DUE TO INCORRECT LOADING
SEQUENCE, ZERO PROCEDURES AND TORQUE ARMS THAT ARE NOT IN BALANCE
WITH A SLIGHT PRE-LOAD IN THE DIRECTION TO BE CHECKED.