19
Control
To read the current baud rate
: read register 21.
To change the baud rate
: write a value from the table above to register 21.
Note:
When changing the instrument’s baud rate, the baud rate for the COM port must
change in time to successfully receive the response confirming the new baud rate. If it
does not, then the baud rate will change on the instrument, but the response from the
serial terminal will not be understood. Since the serial terminal is set to communicate
at a specific baud rate during the initial configuration, you will have to redefine the
terminal baud rate to continue communications.
Setpoint Type
The setpoint type is the signal which will be used to define the setpoint (controllers only).
To read the setpoint type
: read register 516. The values are detailed below.
To change the setpoint type
: write one of the following values to register 516 to set the
setpoint source:
0: Analog input.
1: Digital. The setpoint is saved in flash memory as a power up setpoint.
2: Digital. The setpoint is not saved in flash memory.
Changing the Setpoint
The setpoint is the flow rate that a controller attempts to achieve and maintain by
proportionally changing the position of the valve (controllers only).
To read the current setpoint
: read register 2106. This is the current setpoint. It may differ
from the commanded setpoint due to limited resolution on configured maximum ramping,
indicated by register 524.
To set the desired setpoint
: write the setpoint, as a signed 2-byte integer, to register
33524. The setpoint is equal to the value after formatting with the factory-set number of
decimal places.
Example: if flow units are
SCCM, to obtain a setpoint of 10 SCCM, write 10 to
register 33524.
Communication Watchdog
A communication watchdog (controllers only) will force a zero setpoint and close the controller
valve if no serial communication is received within a user-defined time period. The time is
set in milliseconds, and valid values are 0–5000. If zero, the watchdog is disabled.
Note:
The Communication Watchdog is only available when the setpoint is being set via
MODBUS communication and the Setpoint Source is set to "unsaved digital" (see
).
All other setpoint sources (ASCII, saved digital, analog) are not impacted by the
Communication Watchdog.
To read the current watchdog
: read register 514.
To set a new watchdog
: write a value from 0–5000 to register 514.
Taring the Instrument
Taring adjusts the flow sensor offset so that the current flow value reads zero. This action
gives the instrument a zero reference, ensuring that the instrument provides its most
accurate flow measurements. It is recommended to tare the instrument:
•
After installation
•
If the instrument is hit with any significant impact
•
After any significant changes to the temperature or pressure.
To tare the instrument
: write 0xAA55 (43605) to register 39. Note that performing a tare
will interrupt any currently-executing measurement.
To enable autotare
(controllers only): write 1 to register 515. The instrument will tare flow
