11
Control
Note:
Valve thermal management activates if a setpoint is given for a certain amount
of time with no flow detected. To prevent the valve from getting excessively hot when
driven fully, thermal management is activated, which pulses the valve open/closed until
a change in flow is detected. Once the change is detected, the valve returns to normal
control mode.
Single spaces separate each parameter, and each value is displayed in the chosen instrument
engineering units.
Query Full Data Frame
To read (poll) the entire data frame
:
unit_id
The returned data will be in the format described just above.
Query Specific Data
To read (poll) particular data
:
unit_id
DV
specific_data
specific_data
is the data to be returned, per the table below.
Value
Requested Value
+1
Current flow
+2
Current setpoint
+4
Current temperature
+8
Current valve drive
+16
Gas
+32
Total volume
+64
Current batch remaining
+128
Instrument Status
Add the table values to request multiple data, which will be returned in the order they appear
in this table. The total value must be an integer from 1 to 255:
Example:
unit_id
DV 12
(returns the current temperature followed by valve drive)
Setpoint
The setpoint (controllers only) is the flow rate that the controller attempts to achieve and
maintain by proportionally changing the position of the valve.
To read the setpoint
:
unit_id
S
To set the setpoint
:
unit_id
S
setpoint
setpoint
is the desired flow rate. It is a floating-point value from 0 to the full scale of the
instrument, in the selected flow units for the device. The instrument will accept up to 2.5%
overrange.
Example:
aS 15.44
(set a setpoint of +15.44 [flow units] for instrument A)
Setpoint Source
The setpoint source is the input which will control the setpoint (controllers only).
To read the setpoint source
:
unit_id
LSS
To set the setpoint source:
unit_id
LSS
setpoint_source
setpoint_source
determines which source will control the setpoint, per the table below:
