Emerson Rosemount 8732EM Reference Manual page 114

Advanced Configuration Functionality
8.5.3 Reverse flow
LOI menu path
Use reverse flow to enable or disable the transmitter's ability to read flow in the opposite
direction of the flow direction arrow (see
has bi-directional flow, or when either the electrode wires or the coil wires are reversed
(see Troubleshooting
direction.
8.5.4 Low flow cutoff
LOI menu path
Low flow cutoff allows the user to set a low flow limit to be specified. The analog output
signal is driven to 4mA for flow rates below the set point. The low flow cutoff units are the
same as the PV units and cannot be changed. The low flow cutoff value applies to both
forward and reverse flows.
8.5.5 PV (flow) damping
LOI menu path
Primary variable damping allows selection of a response time, in seconds, to a step change
in flow rate. It is most often used to smooth fluctuations in output.
8.5.6 Signal processing
The transmitter contains several advanced functions that can be used to stabilize erratic
outputs caused by process noise. The signal processing menu contains this functionality.
If the 37 Hz coil drive mode has been set, and the output is still unstable, the damping and
signal processing function should be used. It is important to set the coil drive mode to 37
Hz first, so the loop response time is not increased.
The transmitter provides for a very easy and straightforward start-up, and also
incorporates the capability to deal with difficult applications that have previously
manifested themselves in a noisy output signal. In addition to selecting a higher coil drive
frequency (37 Hz vs. 5 Hz) to isolate the flow signal from the process noise, the
microprocessor can actually scrutinize each input based on three user-defined parameters
to reject the noise specific to the application.
See Chapter 10
108
Detailed Setup > Output Config > Reverse Flow
Section 12.3.3). This also enables the totalizer to count in the reverse
Detailed Setup > Sig Processing > Lo-Flow Cutoff
Detailed Setup > Sig Processing > Damping
for the detailed description of how the signal processing works.
®
Rosemount 8732EM Transmitter with HART Protocol Reference Manual
Section 3.2.3). This may occur when the process