Alicat PROFIBUS - Manual (Page 6)

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Once a unit is tuned to the current process input pressures, a run time
configuration would be used that did not include the PID variable as they take
up system bandwidth.
4.3.2 Data Out Telegram (From Master)
The data out telegram from the master can be configured to contain any
combination of Set-point, Control Register, and Command.
4.3.2.1 Set-point
The format for a set-point is a 4 byte IEEE 32 big endian floating point number.
The set-point is in the same units as the controlled variable specified at time
of order.
An example would be a 200SLPM controller — if the user wanted to set it at
100.2SLPM the set-point would be 100.2 (0x42C8999A).
4.3.2.2 Control Register
The control register controls 4 different aspects of an Alicat Unit.
Each bit in this register only applies to the unit if it makes sense for the unit to
respond. Example if the unit is not equipped with a totalizer the Tare Totalizer
bit will not do anything.
Register Bit Description:
Bit 7 6 5 4 3 2 1 0
Control Register 0 0 0 0 E P V T
T : Tare Totalizer
V: Tare Volumetric
P: Tare Pressure
E: Write Set-point to EEPROM
Logically, the bit works as a return to zero control. This means that once it is
set, in order for another reset to be applied, the control has to set to logic low
and then set to logic high again.