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DDMC Analog Input Process Meter / Controller
Internal Source Calibration (ICAL)
The meter is factory calibrated prior to shipment
for milliamps and volts with calibration equipment
that is certified to NIST standards.
The use of calibrated signal sources is necessary to
calibrate the internal source of the meter. The meter's
internal source is what allows the user to scale the
meter without applying a signal.
Check calibration of the meter at least every
12 months. Each input must be recalibrated
separately.
Notes:
1.
If meter is in operation and it is intended to
accept only one input type (e.g. 4-20 mA),
recalibration of other input is not necessary.
2.
Allow the meter to warm up for at least
15 minutes before performing the internal
source calibration procedure.
The Internal calibration menu is part of the Advanced
Features menu.
1.
Press and hold the Menu button for three
seconds to access the advanced features of the
meter.
2.
Press the Up arrow button to scroll to the Internal
calibration menu (ICAL) and press Enter.
3.
The meter displays either current calibration
(C CAL) or voltage calibration (v CAL), according
to the input setup. Press Enter to start the
calibration process.
Example of Internal Calibration for current
input:
4.
The meter displays low input current message
(C lo). Apply the low input signal and press
Enter. The display flashes for a moment while the
meter is accepting the low input signal.
5.
After the display stops flashing, a number is
displayed with the leftmost digit brighter than the
rest. The bright digit is the active digit that can be
changed by pressing the Up arrow button. Press
the Right arrow button to move to the next digit.
6.
Set the display value to correspond to the input
signal being calibrated, typically
4.000 mA.
7.
The display moves to the high input calibration
(C Hi). Apply the high input signal and press
Enter.
8.
Set the display for the high input calibration, in
the same way as it was set for the low input
calibration, typically 20.000 mA.
The graphic above shows the calibration of the
current input. The voltage input is calibrated in a
similar way.
Tips:
•
Low and high input signals can be any valid
values within the range of the meter.
Observe minimum input span requirements
•
between input 1 and input 2.
Low input should be less than high input signal.
•
However, the low display can be higher than the
high display (i.e. 4-20 mA = 100.0 to 0.0).
Error Message (Error)
An error message indicates that the calibration or
scaling process was not successful.
After the error message is displayed, the meter
reverts to the input prior to the failure during
calibration or scaling and to input 1 during internal
calibration, allowing the appropriate input signal to be
applied or programmed.
The error message might be caused by any of the
following conditions:
5.
Input signal is not connected to the proper
terminals or it is connected backwards*.
6.
Wrong signal selection in Setup menu*.
7.
Minimum input span requirements not
maintained.
8.
Input 1 signal inadvertently applied to calibrate
input 2*.
*Not relevant when scaling the meter.
Minimum Input Span
The minimum input span is the minimum difference
between input 1 and input 2 signals required to complete
the calibration or scaling of the meter.
Input Range
Input 1 & Input 2 Span
4-20 mA
0.15 mA
0.10 VDC
±10 VDC
42
Instruction Manual
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