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5.10 Advanced Menu
5.10.1 Resetting Accumulated Total
Resetting the accumulated total can only be done at this level of the Advanced Menu; by PIN
protecting the instrument it is possible to remove the ability of an operator to reset the
accumulated total. Once the accumulated total is reset it is not possible to recover the value
which was in the accumulated total – it is advisable to record the accumulated total value
before resetting.
5.10.2 Rate Damping
Flow Rate Damping is used to smooth out fluctuating flow input signals in order to provide a
stable Rate Display and Analogue Output. Most input signals are reasonably stable and need
only the default Rate Damping setting, however for systems with large flow fluctuations the
Rate Damping setting may need to be increased.
If the user requires quick visual indication of changes to a system’s flowrate (either on the
Rate Display, or in the Analogue Output) this can be accomplished by reducing the Rate
Damping setting. To remove all damping from the flow rate calculation Rate Damping can be
set to zero.
5.10.3 Low Frequency Cut-Off
The low frequency cut-off parameter is used to adjust the minimum frequency required for
the rate display and analogue output functions. This setting is useful to avoid spikes in the rate
display and analogue output from “apparent flow” which could be caused by movement of
liquid in the pipes of a mobile installation (on a truck etc.), pulsations from a dead-headed
pump, etc.
The default value for the low frequency cut-off is 0.2Hz, and the parameter is adjustable
from 0.1Hz up to 9.9Hz. It is not possible to enable a rate display or analogue output for input
frequencies below 0.1Hz.
5.10.4 Rate Calculation Pulses
The purpose of the ‘Rate Calculation Pulses’ parameter is to determine the number of input
pulses which are used in calculation of the flow rate; the more pulses which are used the more
accurately the Rate Display will represent the average flow-rate of the system. The parameter
is adjustable from 1 to 255 pulses per calculation. For systems using pumps with a non-
uniform rate of delivery (piston pumps or similar) it is important to have a high value for this
parameter as it will produce a stable rate display and analogue output which is representative
of the average flow through the pipe.
For systems with a steady and uniform flow through the pipe, lower values can be used for
this parameter in order to achieve a more responsive rate display and analogue output.
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General