Calibration procedure for TFS
INSTRUMENT CALIBRATION
PROCEDURES
1 GENERAL GUIDELINES FOR CALIBRATION
For an accurate calibration it is necessary to proceed as follows:
a) - The instrument under calibration should be mounted in its case in
order to keep the internal temperature stable.
b) - The ambient temperature should be stable.
Avoid any drift due to air-conditioning or others.
c) - The relative humidity should not exceed 70%.
d) - The instrument must be in ON condition from 20 minutes at least.
e) - Operate, possibly, in an environment with no electromagnetic
disturbances.
f) - During calibration, connect to the instrument one input at a time.
g) - Before to execute each calibration, be sure that the specific
hardware setting has been made (see "Preliminary hardware
setting" paragraph).
For this calibration procedure it is necessary to use calibrators with
the following accuracy and resolution:
ACCURACY
1) For current input:
2) For voltage input : + 0.005% output + 0.001% range + 5 µV
3) For TC input: + 0.005% output + 0.001% range + 5 µV
4) For RTD input:
5) For cold junction compensation: better than 0.1 °C
RESOLUTION
1) For current input: 0.5 µA
2) For voltage input: 100 µV
3) For TC input: 1 µV
4) For RTD input: 10 mΩ
5) For cold junction compensation: better than 0.1 °C
2 PRELIMINARY HARDWARE SETTINGS
INPUT TYPE SELECTION
1) Remove the instrument from its case.
2) Set J1according to the desired input type.
3) Set the dip switch V1to the open condition (see fig. 1).
4) Re-insert the instrument in its case.
+ 0.025% output + 0.0025% range + 0.01 µA
+ 0.02 % + 0.0025 Ω/decade.
3 CALIBRATION PROCEDURE
3.1 FOREWORD
Calibration parameters are divided in groups.
Each group is comprised of two parameters (initial and full scale
values) plus a specific calibration check.
Follows a complete list of the "calibration groups" is reported.
A) TC input
B) Cold junction
C) RTD input
D) Linear mA input
E) Linear 5 V input
F) Linear 10 V input
G) Current transformer input calibration
H) Default calibration data loading
3.2 HOW TO PROCEED
1) Switch on the instrument the display will show "CONF".
2) Push the s pushbutton, the upper display will show "CAL" while
the lower display is blank.
3) Push the FUNC pushbutton to display the first calibration group on
the lower display. Depress FUNC pushbutton more times until the
desired calibration group is reached.
GENERAL NOTES ABOUT CALIBRATION PROCEDURE:
1) During calibration procedure, when the initial or full scale value of a
group is selected and the upper display shows "OFF", pushing the
FUNC pushbutton the instrument will jump to the next parameter
for checking without to modify the previous calibration setting.
In this way it is possible to recalibrate only the desired input or
output.
It is also possibe to make a check of one or more calibration group
without to remake the specific calibration.
Pushing the MAN pushbutton it is possible to scroll back through
the calibration parameters without to memorize the setting.
2) During calibration procedure the serial communication interface
and the time out will be disabled.
A) TC INPUT CALIBRATION
Input J1
Type 1-2 3-4 5-6 7-8 9-10
TC-RTD open close open open open
60 mV open close open open open
5 V close open close open open
10 V open open close open open
20 mA open open open close close
NOTE: the not used jumper can be placed on pin 7-9
2 4 6 8 10
1 3 5 7 9
V1
Fig. 1
J1
A.1) "tL" - INITIAL SCALE VALUE
The lower display will show "tL" while the upper display will show
"OFF"
1)Make the specific hardware setting as described at paragraph 2.
2)Connect the instrument under test to the calibrator as shown in
Fig. 2.
_
3
+
1
Fig.2
3)Set calibrator to 0.000 mV.
4)Push ▲ or ▼ pushbutton, the upper display will change to "On".
5)After few seconds, start the calibration by pushing the FUNC
pushbutton. At the end of this calibration routine, the instrument
will go to the next step.
2