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Reference Manual
00809-0100-4444, Rev AC
Section 5: Advanced Configuration Functionality
January 2015
Advanced Configuration Functionality
5.4.4 Low flow cutoff
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.
5.4.5 PV damping
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.
5.4.6 Signal processing
The 8732EM 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 8732EM 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 8732EM microprocessor can actually
scrutinize each input based on three user-defined parameters to reject the noise specific to the
application.
See Section 7 for the detailed description of how the signal processing works.
Operating mode
The operating mode function can be set to normal mode or filter mode. If set to normal mode,
and the signal is noisy and provides an unstable flow reading, switch to filter mode. Filter mode
automatically uses 37 Hz coil drive frequency and activates signal processing at the factory set
LOI menu path Detailed Setup, Sig Processing, Low Flow Cutoff
Traditional fast keys
1,4,4,4
Device dashboard
2,2,8,5,2
LOI menu path Detailed Setup, Sig Processing, PV Damping
Traditional fast keys
1,4,4,5
Device dashboard
2,2,8,1
LOI menu path
Detailed Setup, Sig Processing
Traditional fast keys
1,4,3,1
Device dashboard
2,2,8,6
LOI menu path Detailed Setup, Sig Processing, Operating Mode
Traditional fast keys 1,4,3,1
Device dashboard 2,2,8,5,1