The Interface Solution Experts
17
HIM
Smart HART
Loop
Interface and Monitor
Configuring Analog Output Trimming
The
Analog Output Trimming section of the software
allows you to match the HART monitors analog output
to the output measured by a calibration device. This
will require a calibrated multimeter, such as a HP Model
3478A or equivalent, accurate to ±0.009%.
Note:
Trimming the analog output of the monitor
nullifies any scaling that may have been
performed in the Scaling tab.
User Trimming
To trim the device, attach a multimeter to the analog
output, then click the
Fix Output at Low Point button.
Read the value on the multimeter, enter it into the
Measured Output Loop Current portion of the Trimming
box, and press
Trim. Repeat this sequence until the
analog output matches the minimum point (4mA for a
4-20mA output) when you click the
Fix Output at Low
Point button.
After the low point is trimmed, press the
Fix Output at
High Point button. Read the value on the multimeter,
enter it into the
Measured Output Loop Current portion
of the
Trimming box, and press Trim. Repeat this
sequence until the analog output matches the
maximum point (20mA for a 4-20mA output) when you
click the
Fix Output at High Point button.
When finished, press the
Unfix Output button.
Figure 13.
Trimming Window
Fix Current Utility
The
Fix Current Utility allows you to force the HIM to
output any current value from 0-20mA. This can be
used to match the calibration of your other equipment.
To fix the current, simply enter the value in the
Current
box (in mA) that you want the HIM to output, and click
Fix Output. When you are finished, make sure to
press the
Unfix Output button so that the HIM can
return to normal operation.
