Figure 33- Reference Plane R For Flanged And Threaded Connections - Honeywell SLG 700 Option Manual

Probe Length:
The distance from the transmitter's Reference Plane to the end of the probe. This parameter is
normally entered by the factory based on the model number ordered and does not need to be changed.
See SLG 700 Transmitter User's manual #34-SL-25-11 for trimming probes.
For coax probes and rod probes without a centering disk the distance to enter is the distance to the
physical end of the probe.
For rod probes with a centering disk attached the distance to the top surface of the disk should be
entered.
For wire probes with an end-weight attached it should be the distance to the top of the end weight.
Reference plane R
The GWR transmitter inherently measures the time of flight of radar pulses that reflect off the
boundary between two different mediums. This time is first transformed into a measure of the distance
between a fixed point on the transmitter body, referred to as the Reference Plane, and the boundary
between the two medium. The Reference Plane has been chosen to be a flat machined surface near the
probe connection point. Figure 33 shows the location of the Reference Plane, denoted as R, for the two
basic methods of connecting the transmitter to the tank, either threaded or flanged. Refer to the Radar
Level Measurement section in the SLG 700 Transmitter User's manual #34-SL-25-11.

Figure 33- Reference plane R for flanged and threaded connections

Page 136 FOUNDATION Fieldbus Option User's Guide Rev. 3.0