The flow sequence can be paused, resumed and ended by the user at any point in the flow
sequence.
Transmitter outputs therefore change state according to the dosing sequence or operator
commands. For optimal dosing control the minimum number of components between the
flowmeter and the dosing valves must be employed. The dosing function must be configured for
the type of valve used for dosing:
● One on/off valve:
Dosing controlled by a single discrete (Open/Closed) valve. The valve opens completely
when the dosing begins, and closes completely when the dosing Amount is reached.
● Two on/off valves:
Dosing controlled by two discrete valves (a primary valve and a secondary valve). One valve
opens at the beginning of the dosing; the other opens at a user-defined amount. One valve
stays open until the end of the dosing; the other closes at a user-defined amount.
See examples below (Page 148) of some different opening and closing options.
● Control valve:
Dosing controlled by an analog valve configured in three stages as fully open, partially
closed, and fully closed. See example below (Page 148) of the three-positional Control
valve.
Dosing setup procedure
The dosing functionality is configured via HMI. Menu 2.4 "Inputs/Outputs" determines how the
transmitter will use the inputs and outputs for dosing control. Menu 2.5 "Dosing" independently
determines the sequencing of the outputs to achieve the user’s desired result.
The dosing function provides:
● three dosing valve control mechanisms (One on/off valve, Two on/off valves or Control
valve)
● dosing of mass flow, volume flow, standard volume flow or fraction (mass flow or volume
flow)
● five independently configurable recipes
● flexible discrete or analog valve control
● fault handling – time and amount monitoring
Configure the dosing function as follows:
1. Basic dosing parameters common for all recipes in "Dosing" (menu item 2.5)
– Select valve control functionality at parameter "Dosing Mode"
– Select measured process value for dosing at parameter "Process Values"
2. Individual recipe(s) in menu items 2.5.5 to 2.5.9 as required
– Setup dosing name, amount, unit and compensation
– Select valve control sequence
– Select fault handling configuration
3. Output(s) in "Inputs/Outputs" (menu item 2.4).
4. Input for dosing control in "Inputs/Outputs" (menu item 2.4).
Parameter assignment
8.2 Functions
SITRANS FC330
146 Operating Instructions, 01/2019, A5E44030648-AB
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