30
MAINTENANCE
6. Calibration
6.1
CLOSED-BOX CALIBRATION
The 6400 features closed-box calibration. The advantage of closed-box calibration is that the user
does not have to disassemble the case or make mechanical adjustments.
The torque readout and auxiliary input can be calibrated using external reference sources. Correction
factors for offset and gain are stored in nonvolatile memory. They remain in effect until the user or
the calibration house updates them.
The front panel displays the actual values for the ZERO and GAIN correction factors. Record these
values before calibration. In the unlikely event of a Torque Transducer Display failure, it can be re-
initialized by pressing and holding the STORE and RECALL buttons while turning the power on.
All internal memory and setups will be lost. After re-initializing, reprogram the GAIN and ZERO
values into memory.
6.2
CALIBRATION SCHEDULE
Calibrate the 6400:
•
After any repairs are performed.
•
At least once a year; more frequently to ensure required accuracy.
6.3
BASIC CALIBRATION PROCESS
The basic calibration process consists of four procedures which must be performed in the following
order:
1. Initial Procedure
2. Torque Offset and Gain (computer or manual)
3. Auxiliary Input Offset and Gain (computer or manual)
Items needed for calibrating the 6400:
•
External voltage reference of 0 to 10 volts DC
•
Digital multimeter (DMM)
Both instruments should have a VDC accuracy of 0.05% or better.
6.3.1
I
NITIAL
C
ALIBRATION
P
ROCEDURE
1. Allow the 6400 to stabilize in an environment with:
•
An ambient temperature of 18°C to 25°C.
•
Relative humidity less than 80%.
2. Turn on the 6400.
3. Allow the 6400 to warm up for at least 30 minutes.
4. Go to computer or manual calibration sections.