Liquid Controls SP3850 - Manual (Page 69)

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SP3850 Flow Computer
Flow Equation
A recognized relationship between the process parameters for flow, temperature, pressure and density used in flow
measurements.
Flow Signal Timeout
The Flow Signal Timeout allows the user to enter a timeout of 0 to 99 seconds. If a batch is “Filling” and zero flow
persists for more than the user entered time then the batch will be aborted. This prevents over flows due to faulty
flow sensors and/or wiring.
Flowing Z-Factor
The mean Z-Factor under flowing conditions of temperature and pressure for a specific gas.
Follow, Alarm
Alarm relays which are non latching and whose output state is based solely on the comparison of the current
process value and the alarm setpoint (trip point).
Function Key
A key on a push-button panel or keyboard (whose function is described by the key label) used to perform an
instrument function or special routine.
Handshake
A means of controlling the information flow between two pieces of equipment to prevent the sending device from
transmitting information at a rate faster than what can be accepted by the receiver.
Gas Cor. Vol Eq.
An equation where the corrected volume flow of gas at STP is computed from measured volume flow,
temperature and pressure as well as stored gas properties.
Gas Mass Eq.
An equation where the mass flow of a gas is computed from measured volume flow, temperature and pressure as
well as stored gas properties.
Hysteresis
The relay hysteresis is a "dead band" setting which allows the relay to remain energized for a given amount below
the setpoint. This is used to prevent relay chatter when the process value is near the setpoint value.
Example: If the Preset is set at 100, and the hysteresis is set at 10, the relay will energize when the rate, temp or
dens. reaches 100, the relay will remain energized until the reading falls below 90.
Input Termination
Input signal lines on digital inputs often require pullup or pulldown resistor configurations to operate properly
with different sensor configurations. The SP3850 contains such resistors and may be enabled via the setup menu.
Inlet Pipe Bore
The internal pipe diameter upstream of the flow measurement element.
Inhibit Totalizer
"Inhibit Total" is a Control Input 1 setting that is used to stop the totalization. If enabled, a voltage level on control
input 1 will inhibit the total as long as the voltage is present. This feature is useful during meter proving and in
applications that provide a sensor to signal the flow computer when fluid is present.
K-Factor
A scaling factor derived from the pulses produced by a flowmeter output, expressed in pulses per unit (i.e. pulses/
gallon)
Limit Setpoint
An alarm trip point setting which specifies the value or magnitude of a process parameter necessary to activate an
alarm indicator or control relay.
Linear Flowmeter
A flow measurement device whose output is proportional to flow.
Linearization
The mathematical correction of a nonlinear device. The SP3850 uses a linearization Table which is made up of
input/output values and makes interpolations of the table to arrive at a "linearized" measurement.
LinTbl
Abbreviation for Linearization Table.
Low Pass Filter
A low pass filter passes low input frequencies while blocking high frequencies. In the SP3850, this is the
maximum input count speed to be encountered in an application. It is expressed in counts per second (Hz).
12. Glossary Of Terms (Continued)