Process Control
January 2023
•
Rev. 0
• Standard Devices User Manual
20
Repeat a Batch
•
For an identical batch, press
RESET
.
Flow begins immediately.
•
For a new batch of a different size, press
BATCH
,
and select the new batch size. If there is a non-zero
setpoint, flow begins as soon as
SET
is pressed.
Pause or Cancel a Batch
•
To pause flow while a batch is in progress, change the
setpoint to
0
by pressing
SETPT → CLEAR → SET
within
the
totalizer menu
. This does not stop the timer. To
resume, change the setpoint to a non-zero setpoint.
•
To remove a batch setting, press
BATCH → CLEAR
→ SET
. Deleting the batch does not affect the
setpoint. Flow will continue at the setpoint rate.
!
Warning:
Flow resumes immediately at the current
setpoint when batch dispensing is turned off.
✓
Note:
The controller retains batch size
across power cycles. The batch size must
be manually cleared to remove it.
Valve Drive Percentage Display
MENU
→
CONTROL
→
Show Valve
The valve drive is represented as a percentage of the total
possible voltage driven to the valve. While drive percentage
does not directly correlate with percentage open, a drive
percentage of 0% indicates the valve is not open.
Viewing the valve drive percentage can be helpful for
troubleshooting. An increase in percentage over time likely
indicates a blockage in the system where more voltage is
required to drive the valve to attain the same amount of flow.
This information may be displayed on the
main display
and/
or as part of transmitted serial data. There are four valve
display options:
•
None
:
No valve information is displayed.
•
Main Screen
:
Only on the main display.
•
Digital Data
:
Only in the serial data frame.
•
Screen and Digital
:
Both the main
display and serial data frame.
Control Loop
The control loop manages what parameter a controller
controls as well as how the controller reacts to changes
within the system.
Controlled Variable
MENU
→
CONTROL
→
Control Loop
→
Control
The controlled variable is the measurement the controller
attempts to regulate to the given setpoint. Controllers can only
control one measurement at a time, but they still measure the
other variables during that time. Below are the lists of possible
variables each controller can control.
Mass Flow Controllers
Mass flow controllers can control mass flow, volumetric flow,
pressure (absolute or gauge) and the valve drive.
Liquid Controllers
Liquid controllers can control volumetric flow, gauge pressure,
and the valve drive.
Pressure Controllers
Pressure controllers can only control the pressure of the
device. Selectable control loop variables include pressure
(absolute, gauge, or differential) and valve drive.
✓
Note:
When pressure is the selected variable,
all controllers with upstream valves control the
outlet pressure. Those with downstream valves
control upstream back pressure, but these devices
must be configured for this type of control.
!
Warning:
When changing the control loop,
the PID settings may need adjusting for
optimal stability and speed of response.
V
alve display menu
Valve percentage on the
main
display
, above the large numbers.
