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FC-21 Flow Computer
5.2 General Operation
The unit can display: Rate, Total, Grand Total, Temperature, Density, Presets
and Time of Day. The Temperature and/or Density can be displayed even if
you are using the Volumetric Flow Equation (a Temperature or Density sensor
must be installed). The unit can perform Mass or Corrected Volume equations
using a temperature or density sensor (these equations can be computed
without Temp/Dens sensors by using user defined default values). The unit can
be programmed to perform Ratemeter/Totalizer or Batching functions (see
section 6.3, SELECT INSTRUMENT Submenu).
5.3 Ratemeter/Totalizer Operation
The Ratemeter/Totalizer mode is used primarily to monitor flowrate and
accumulated total. The relays can be used to trigger flow, total, temperature or
density alarms.
5.3.1 Password Protection for Rate/Total mode
After an Operator and/or Supervisor Password is entered in the setup mode
(see section 6.3, SETUP PASSWORD submenu), the unit will be locked. The
unit will prompt the user for the password when trying to perform the following
functions:
Clear Total
Clear Grand Total
Enter Menu
Edit Preset 1 (PRE 1 Key)
Edit Preset 2 (PRE 2 Key)
The Supervisor password should be reserved for supervisors. The Supervisor
password will allow access to restricted areas of the Setup and Test menus.
5.3.2 Relay Operation in Rate/Total mode
Up to four relays are available (two standard) for alarm outputs. The relays can
be assigned to trip according to rate, total, temperature, density readings or
general system alarms. The relays can be programmed for low or high alarms.
Preset 1 (RLY1) and Preset 2 (RLY2) are easily accessible by pressing the
PRE 1 or PRE 2 key on the front panel. Preset 3 and Preset 4 are accessible
only through the setup menu.
5.3.3 Pulse Output in Rate/Total mode
The isolated pulse output (open collector) is menu assignable to Volume Total,
Corrected Volume Total or Mass Total. The pulse output duration can be set for
10mS (50 Hz max) or 100mS (5 Hz max). A pulse output scale factor (pulse
value) can be set to scale the pulse output. The pulse output is ideal for
connecting to remote totalizers or other devices such as a PLC. See section
1.3 for electrical specifications.
5.3.4 Analog Output in Rate/Total mode
The analog output is menu assignable to correspond to the Volume Rate,
Corrected Volume Rate, Mass Rate, Temperature, Density, Volume Total,
Corrected Volume Total or Mass Total. The analog output is ideal for "trend"
tracking using strip chart recorders or other devices.
General
Operation
Rate/Total
Operation
Password Protection
(Rate/Total mode)
Relay Operation
(Rate/Total mode)
Pulse Output
(Rate/Total mode)
Analog Output
(Rate/Total mode)
