Reference Manual
00809-0100-4841, Rev. AA
May 2007
Rosemount 3490 Series
4-54
Pump-down can be initiated automatically at pre-set intervals. A digital input
can also initiate pump-down at any time and this will re-set the interval before
the next pump-down. For details on configuring a digital input, see Section
“Digital Inputs IN1 and IN2“ on page 4-34.
Pump-down will automatically stop when the parameter D800 (PV) is zero or
after 20 minutes (maximum) if a pump-down duration (P274) has not been
programmed, whichever is the shorter period.
P272 Pump down RL (Factory default is 00000)
This is for allocating individual relays to pump-down duty. However, the mode
of the relay must be Set point, Assist or Standby. Each of the five digits
represents a relay. Relay RL1 is selected by editing the first digit to a "1".
Similarly, relay RL5 is selected by editing the fifth digit. To de-allocated, edit
the appropriate digit back to a "0".
P273 Pump down Int (Factory default is 000:00 h:m)
This defines a fixed interval (hours and minutes) between pump-downs.
P274 Pump down Dur (Default setting is 00:00)
This defines the period (hours and minutes) that the relay will remain
energised for the pump-down. (Safeguards may extend or reduce this period -
see Section “Relay Safeguard Options“ on page 4-43.)
NOTE:
For any of the alarms below to be indicated by a relay or current output, an
indication method must be selected. See Section “Alarm indication selection“
on page 4-60 for details.
D845 Next pump-down h:m (Factory default is 000:00)
This shows the time remaining before the next pump-down is invoked. Display
shows 000:00 if pump-down is in progress or it is not used.
Custom
(Special Control Function - see Table 4-12 on page 4-45)
Menu:
MAIN MENU / SETUP / [CONTROL UNIT /] DUTY(Mode) / CUSTOM
P250 Start On (Factory default is "None")
Relay energises when the criteria, as set by an option code, is true. See Table
4-14 on page 4-56.
P251 Stop On (Factory default is "None")
Relay de-energises when the criteria, as selected by an option code, is true.
See Table 4-14 on page 4-56.
P252 Stop If (Factory default is "None")
Relay de-energises when the criteria, as selected by the option code, is true.
See Table 4-14 on page 4-56. This is a fail-safe for P251.
P253 Start Time (Factory default is "7:00" - i.e. 7AM)
This defines the clock time that a Custom relay operation will
begin (if P250 = "Time"), or end (if P251 = "Time").
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