|
Simple functions such as customising the Elite's or
RVSx's alpha numeric display to indicate real units like flow rates, or creating
multi-speed, multi-acceleration rate applications, to more complex functions
such as crane control with limits, and multi-pump lead pump systems may
be configured.
Once the control system is configured within VYSTA,
the program is then compiled and downloaded via the inbuilt
RS-232 serial port. The controllers have the capability to run this program
as a real-time digital control system.
The Elite and RVSx Series of AC motor controllers are sophisticated
enough to store multiple application programs. Hence a pump controller
may become a crane controller by simply selecting the appropriate program
within the Elite.
VYSTA can be separated into three main components:
the Screenlist Editor, the Schematic Editor, and the Compiler.
The Screenlist Editor
The Elite Series of AC motor controllers
and RVSx Series of soft starters have a two line by 16 character remote mountable LCD, complete with a five-button
membrane keypad. The remote display is used for editing and displaying
drive parameters and variables. The display and functionality of the buttons
can be totally customised with VYSTA. Screens can be modified, added or
deleted as required. Variables may be scaled and displayed as required.
This is useful in depicting real units such as flow-rates, linear speed
and ratios.
Data can also be entered via the keypad, such as scaling factors, ratios,
setpoints and parameter adjustments. More than one screen list per VYSTA
program is supported. For example, this enables selection of a truncated
Screenlist or a full Screenlist. Hence VYSTA provides a totally customised man-machine interface for a specific
application.
top ^
The Schematic Editor
The Schematic Editor employs a Graphical User Interface (GUI) where
a logic schematic is created. The schematic is easily configured, by selecting
the appropriate function blocks or icons, and linking or wiring them together
using drop and drag techniques.
The platform is very flexible and contains the major process control
function blocks that are typically available in digital loop controllers
and PLCs. Salient function blocks include: PID loops, Boolean logic functions,
counters, comparators, analogue switches, ramp controllers, rate limiters
etc. Also standard arithmetic operators are available such as addition,
division, multiplication, square root extraction, integration and trigonometric
functions.
Program variables can be created within VYSTA. The platform also allows
access to many of the controller's internal control variables such as frequency,
current and torque. The VYSTA program has the ability to control any internal
parameter that is usually accessed by the screen or via serial communications,
such as speed or torque operation, control of acceleration deceleration
and stop modes.
Alternatively the controller's analogue and digital I/O can be monitored
and controlled independently from the standard program functionality. This
enables the controller to perform its usual motor control tasks, but also to
act as a remote terminal unit for another part of, or another process control
system.
As the controllers use FLASH memory for their program storage, program and
drive firmware downloads are performed exclusively via the controller's inbuilt
serial port. There is no requirement to change EPROMs.
top ^
The Compiler
Once the Screenlist and Schematic components are complete, the file
is saved in a netlist format. The VYSTA netlist file is then compiled and
downloaded into the controller through an RS-232 serial link. Errors in the
program configuration are detected and displayed during the compilation
process. Multiple VYSTA programs can be stored in the controller. The only limitation
is memory space. The standard Elite or RVSx configuration is always available after
additional VYSTA programs are downloaded. The desired program or mode of
operation is selected via the digital display keypad.
These features employed in both the Elite and RVSx Series provide unparalleled flexibility
and adaptability within AC motor controller applications.
 |
|
 |
|
VYSTA programs are configured within in the Screenlist Editor and
the Schematic Editor. |
|
Function blocks are selected from
an innovative oval menu. |
|
|
|
|
|
|
|
|
|
Display screens are customised and created within the Screenlist
Editor. |
|
A control schematic is configured
using drop and drag techniques
within the Schematic Editor. |
|
|
|
top ^
|
VYSTA Virtual Automation Lead Pump
Control System
|
The Virtual Automation lead pump control system will optimise constant
pressure pumping of up to four pumps, resulting in significant energy savings
and reduced machinery wear and tear.
With this system and Elite series AC motor controller is used to control
the speed of a lead pump and to start and stop up to three fixed speed pumps.
The fixed speed pumps operate at supply frequency in DOL or, for enhanced
system performance, under RVSx soft starter control. The Virtual Automation
lead pump control system incorporates a fully featured control algorithm which
determines how many fixed speed pumps will need to be operating for the
present demand and will operate the lead pump at a variable speed to make up
the demand requirement.
Under normal operating conditions, the response to an increase in demand
initiates an increase in speed of the lead pump. If the lead pump is unable to
fulfil the demand and has already reached full capacity, one of the fixed
speed pumps is switched in. The lead pump then reduces speed to allow the
fixed speed pump to take up the demand.
Conversely when demand decreases the initial response is a speed reduction
of the lead pump. If the fixed speed pumps that are operating at the time in
conjunction with the lead pump (operating at its slowest delivery) are
providing too much flow, one of the fixed speed pumps is switched out. The
lead pump then increases speed to take up demand.
|
The Virutal Automation lead pump system also
incorporates the following special features:
|
-
Pipe Fill - overrides the PID on initial
start up to run the lead pump at a preset speed
until a feedback signal indicates the presence of
fluid in the pipe.
-
Setpoint Ramp - on initial startup or
after a period of no demand, the feedback pressure
may be below the setpoint pressure. To avoid the
effects of this error on the PID, a setpoint ramp
control algorithm overrides the setpoint pressure
and applies a derived setpoint to the PID
controller.
-
Setpoint Flow Compensation - as demand
increases the number of fixed speed pumps running
increases. To ensure delivery pressure remains
constant, the applied setpoint is automatically
incremented as the system flow rate increases to
compensate for the increased pressure drop.
-
Fixed Speed Pump Duty Sharing - decides
which pump to switch, depending on the value of
the fixed speed pump hour counters, to keep the
running hours for all fixed speed pumps the same.
If this function is disabled then the selection of
fixed sped pumps will be in numerically increasing
order.
-
Cavitation Protection - when cavitation
is detected the lead pump is momentarily stopped
then allowed to continue operation.
-
Further protection and performance features
include: high pressure shutdown, no flow
protection, minimum pressure protection, automatic
turn off, fixed speed pump start/stop control -
with slow or fast response modes, PID bypass
speeds, no demand shutdown, demand turn on, fixed
speed pump inhibit, optional irrigation timer
allows pumps to run for a pre-set time then shut
down, pressure display in engineering units and
custom status screens.
|
|
|
top ^
|
|
The Elite and RVSx Series have several input modes that allow the digital inputs
to be configured in various arrangements. One of these configurations uses
three of the digital inputs to select from seven preset speed references
plus zero.
Some industrial processes require a larger number of presets than provided
by this standard configuration. VYSTA allows the customisation of preset
speeds, limited only by the number of digital inputs.
By using a binary combination of four of the digital inputs a larger
data table can be constructed using VYSTA, that can provide up to fifteen
preset references plus zero. It is possible to expand the data table further
using more of the digital inputs and provide for a greater number of preset
speeds.
This allows for multiple production line speeds to be digitally selectable.
|
|
 |
|
|
top ^
|
|
