ABB 266MST - Liquid Level on Closed Tanks (Dry Leg); Liquid Level on Closed Tanks (Wet Leg); Liquid Level Measurement with Open Tanks

26 OI/266/HART-EN Rev. M | 2600T Series Pressure transmitters
5 Mounting
5.14.3 Liquid level measurements on closed tanks
and non condensable fluids (dry leg)
— Mount the transmitter at the same height or below the
lowest level to be measured.
— Connect the + (H) side of the transmitter to the bottom of
the tank.
— Connect the - (L) side of the transmitter to the upper part
of the tank, above the maximum level of the tank.
5.14.4 Liquid level measurement with closed tanks and
condensable fluids (wet leg)
— Mount the transmitter at the same height or below the
lowest level to be measured.
— Connect the + (H) side of the transmitter to the bottom of
the tank.
— Connect the - (L) side of the transmitter to the upper part
of the tank.
— Fill the vertical section of the connecting line to the upper
part of the tank with a compatible liquid through the
dedicated filling tee.
Figure 33: Level measurement on closed tank with dry leg
Figure 34: Level measurement on closed tank with wet leg
5.14.5 Liquid level measurement with open tanks
— Mount the transmitter at the same height or below the
lowest level to be measured.
— Connect the + (H) side to the bottom of the tank.
— Vent the “–” (L) side of the transmitter to the atmosphere
(in this case a gauge pressure is shown; the (L) side is
already vented to the atmosphere).
Figure 35: Level measurement on open tank with P style transmitter