Yamatake Corporation
ST3000 Smart Transmitter Series 900 Electronic Differential Pressure/Pressure Transmitter
5-21
5-3-3 :Liquid Level Measurement of Open Tank and Closed Tank (Dry
Leg)
5-3-3-1 Preparation for Measurement
WARNING
• Place the process in the manual control mode.
If the process is in the automatic control mode, switch to manual before performing
work.
• Drain poisonous fluids carefully, taking provisions to protect workers.
• Check that the differential pressure output valve (main valve), the drain
valve, the gas vent plug (refer to "Figure 4-12 Example of Piping".) are
closed, as well as the high pressure side and low pressure side stop valves
of the 3-way manifold valve. Also, make sure that the equalizer valve of
the 3-way manifold valve is open.
Calculating setting range
Calculate the setting range. Refer to "5-10 : Set Range Calculation for Liquid Level
Measurement".
Procedure
Perform zero-point adjustment and introduce process pressure into the transmitter by
this procedure:
Zero-point calibration
Step
Description
1
Open the drain plugs and the stop valves of both the high-pressure side
and the low-pressure side. Open the pressure receiving part to the air.
If fluid remains in the pressure receiving part, blow it to drain.
2
Refer to procedure 2 in page 5-10 and perform zero-point calibration.
3
After completing zero-point calibration, close the high-pressure side drain
plug and the high-pressure side stop valve.
