PLX51-HART-4I / PLX51-HART-4O
♦
HART Input/Output
Diagnostics
Multidrop Field Devices
User Manual
ProSoft Technology, Inc.
Page 116 of 127
5.6.2 PLX51-HART-4O Calibration:
To re-calibrate a PLX51-HART-4O module:
1
Ensure the channel configuration has both the
Prog/Fault Freeze
and
Comm
Fail Freeze
options checked, and that the module is disconnected from the
EtherNet/IP (Logix), DNP3 or Modbus source.
2
Click the
Set 4 mA
button. The output current will change to 4 mA.
3
Using an external meter, measure the actual loop current and enter the milliamp
value in the
Low Value
(4 mA)
Actual Measured
textbox.
4
Click the
Set 20 mA
button. The output current will change to 20 mA.
5
Using an external meter, measure the actual loop current and enter the milliamp
value in the
High Value
(20 mA)
Actual Measured
textbox.
6
The new
Span
and
Offset
calibration settings will be automatically calculated.
(See figure below).
7
Press
Accept
to write these new calibration figures to the module.
8
The Calibration Type will then change to User Calibration, to reflect the changes.
Figure 5.26 – User Calibration - Output
Important
: Before commencing with output calibration ensure that it is safe to do so. The field device
should be either isolated from the process mechanically or the process be in such a state that variations
in the output signal cannot cause a disruption to the process. Failure to do so could result in severe
equipment damage and personal injury.
Important
: The
Set 20 mA
and
Set 4 mA
buttons will be disabled if the configuration has either the
Prog/Fault Freeze
or
Comm Fail Freeze
options not checked.
Important
: If the module’s data source (EtherNet/IP (Logix), DNP3 or Modbus) is not disconnected or
disabled, then the simulated milliamp value will be constantly over-written negating the calibration
procedure.