3. Pump Setup
ORM0043_2
Modulating Controller Application Manual
Page 6
3.1 Pump On Demand
Pump on demand can be used on hydraulic positional
systems and refers to operating a pump to open and/or
close the actuator. To use pump on demand features,
Pump On Demand
must be turned active.
If
Run Pump To Opn
is active then when the actuator is
opening
Pump Output
is set active.
If
Run Pump To Clse
is active then when the actuator is
closing
Pump Output
is set active.
In certain cases the pump is required to continue running
for a set time once the actuator has stopped moving,
either to prevent constant stop/start of the pump, or to
build pressure at the actuator limits.
To use this feature
Pump Run On
time should be set to
the required run on time and once the actuator is stay
put, the
Pump Output
will be held active for the duration
of the run on time. If a pump run on is not required then
the
Pump Run On
time should be set to zero seconds.
3.2 Pump On Pressure
Pump on pressure can be used on hydraulic positional
systems and refers to operating a pump to maintain
pressure in an accumulator. To use pump on pressure
features,
Pump On Pressure
must be turned active.
Two methods of maintaining pressure can be used
–
using a pressure transmitter or using pressure switches.
If using a pressure transmitter then
Press Swtch Ctrl
should be turned off and
Accum Pressure
should be
linked to an analogue input to indicate the accumulator
pressure.
Four pressure set points can be set to provide actions
based on the accumulator pressure.
Pump Start SP
is the minimum desired accumulator
pressure.
Pump Stop SP
is the maximum desired
accumulator pressure. When
Accum Pressure
drops
below the
Pump Start SP
, the
Pump Output
is latched on
and will remain on until
Accum Pressure
rises above the
Pump Stop SP
at which point the
Pump Output
will be
turned off.
Low Pressure SP
is a low pressure alarm set point which
is used to indicate that the pump is not able to build
pressure in the accumulator. If the
Accum Pressure
drops below the
Low Pressure SP
for greater
than
Px
Limit Delay
then
Low Press Fault
output is set active. If
Fail On Pump Flt
is active then the actuator will position
based on the fault override settings.
High Pressure SP
is a high pressure alarm set point which
is used to indicate that the pressure has exceeded the
maximum allowable accumulator pressure possibly
caused by the pump continuously running. If the
Accum
Pressure
rises above the
High Pressure SP
for greater
than
Px Limit Delay
the
High Press Fault
output is set
active.
If using pressure switches to control accumulator
pressure then
Press Switch Ctrl
should be set to active.
If using a single pressure switch then
Single Px Switch
should be set active and the pressure switch must be
linked to
Pump Start Swtch
. The application
automatically sets
Pump Start Swtch
and
Pump Stop
Swtch
active and off based on the single pressure switch
status.
If using two pressure switches then
Single Px Switch
should be turned off, the switch indicating low pressure
should be linked to
Pump Start Swtch
and the switch
indicating high pressure should be linked to
Pump Stop
Swtch
.
For both cases, if the
Pump Start Swtch
is active for
greater than
Px Limit Delay
, the
Pump Output
is latched
on and will remain on until the
Pump Stop Swtch
is
active for greater than
Px Limit Delay
at which point the
Pump Output
will be turned off. The
Px Limit Delay
can
be increased to prevent signal noise causing the pump to
start and stop frequently, or set to zero to cause the
operation to be instant.
For both pressure switch control and pressure
transmitter control, if
Manual Stop Pump
is active then
when the controller is in Manual mode and the switch is
in the centre,
Pump Output
is set off. This is such that if
there is an issue with the pump, the pump can be
stopped instantly by going into Manual mode.
NOTE: If in Manual mode,
Manual Stop Pump
is active
and the switch is turned either away or towards the
pump will operate as normal such that pressure can be
built in the accumulator when trying to position the
actuator.
3.3 Accumulator Pressure Signal Fault
If
Pump On Pressure
is active and
Press Swtch Ctrl
is off
(i.e. in accumulator pressure transmitter control) and
Accum Pressure
signal is in fault for greater than
Sig
Fault Delay
then
Acc Press Fault
output is set active. The
Pump Output
is also turned off as the pump cannot be
run without a valid pressure signal as it cannot be known
if the maximum pressure limit has been reached.
