4-7
1. The electronics should be located in a place where the ambient
temperature does not change rapidly or vary by more than 10 to
15°F (26 to 29°C).
2. When commissioning the electronics, the flowing fluid
(condensate/water
for steam service) could bring the sensor to a temperature
significantly different than the temperature during normal
operations. In this situation, perform another “zero” calibration at
least 60 minutes after the ProPlate
has been commissioned. The sensor temperature can be monitored
using a HART-based communicator, as described in the following
“Zero or Wet Calibration” section.
Although the above effects are relatively small, they significantly affect
the accuracy of the ProPlate when used with low flows.
Periodic “zero” calibration and/or commissioning is recommended to
maintain the accuracy of ProPlate. The frequency of this type of
maintenance should be established for each individual application.
Zero or Wet Calibration
Follow this procedure to obtain a true zero at static or “pipe” pressure:
1. Close low side valve ML to prevent generating differential
pressure.
2. Open equalizer valves:
• For 5-valve manifolds, open valves MEH and MEL.
• For 3-valve manifolds, open valves ME and high side MH.
COMMISSIONING Complete the following tasks before beginning the
commissioning procedure:
1. Power the ProPlate, if required.
2. Connect an appropriate readout instrument so the differential
pressure signal can be monitored.
3. Identify the manifold equalizer valves by their ME prefix.
• 5-valve manifolds have two equalizer valves, MEH and MEL.
• 3-valve manifolds have one equalizer valve, ME.
4. Close all valves before commissioning the system. See Figure 2-26
on page 2-19 through Figure 2-32 on page 2-23 for valve
identification while following the procedures given below.
Do not open the ME Valve when steam line is pressurized, as the water legs can be
removed.
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