49
11.2.2
PRESERVATION OF STORED DATA
When the batteries are removed, the data (recorded measurement values, alarm
thresholds) are preserved. The date and time must be reset if the batteries are out
for more than 2 minutes.
11.3 CHECK OF ACCURACY
11.3.1
OBJECT AND EQUIPMENT NECESSARY
Regular checking serves to verify the accuracy of the clamp and thereby detect
any need for an adjustment.
11.3.2
EQUIPMENT
Standard loop resistance available as an accessory. Simulates 5 loop resistance
values.
11.3.3
PROCEDURE
Place the calibration loop in the jaws of the clamp. Set the function switch of the
device to
Ω+A
, then compare the measurement displayed with the value marked
on the segment placed in the clamp. Repeat this process for each standard value
of the calibration loop.
Depending on the measurement errors found, you may decide that your clamp
must be calibrated. The first step is to carry out the adjustment procedure
described in §11.4, before getting in touch with your supplier.
■
Standard loop values: 7.9Ω
/
12.4Ω
/
22Ω
/
49.5Ω
/
198Ω.
■
Accuracy of these values 0.3% typical, 0.5% max.
Remark: the accuracy of the device must be added to the accuracy of the
standard values.
11.4 ADJUSTMENT
11.4.1
OBJECT AND EQUIPMENT NECESSARY
Regular adjustment is required; the more intensively the device is used, the more
often it will have to be adjusted.
The user can perform 2 adjustment operations in addition to restoring the factory
settings, directly on the clamp, in the SET-UP position.
11.4.2
EQUIPMENT
Standard loop resistance available as an accessory. Simulates 5 loop resistance
values.
