Fridgewatch 2100 Controller Mk4
Section 3
Publication 3-58
Issue 1.1 : 01/08
Page 127 of 152
If the Watchdog is disabled, the MICRO OK indicator is illuminated all the
time, regardless of any fault that may be present.
CAUTION
The Watchdog must ALWAYS, without exception, be
enabled when Fridgewatch 2100 is controlling
refrigeration equipment.
If the Watchdog is enabled but the MICRO OK indicator is not illuminated
and the voltage is correct at the +5 V tab, it is probably necessary to
change the RAMP4 card. However, it is recommended to make several
attempts to reset the processor, powering down between each attempt,
before taking this drastic step.
As the Fridgewatch 2100 Controller settings data is contained in RAM,
removal of the RAMP4 card will erases these settings. Removal for
replacement should therefore only be attempted as a last resort.
(a)
Check to make sure all Operator and Configuration Settings have
been correctly recorded in 16. Appendix 3 - Settings Record.
Settings must be restored afterwards.
(b)
Observe monitoring point P3 on the Fridgewatch 2100 display and
make a note of the number of hours the compressor has run.
(c)
Stop the plant. Turn off the power supply to the Fridgewatch 2100
by turning the main isolator on the lower control panel door to the
‘off’ position.
CAUTION
Never remove or replace an electronic card with the
Fridgewatch 2100 power supply turned on.
(d)
Open the panel door. The RAMP4 card is located on the back of
the panel door.
NOTE: electronic cards are easily damaged by static
electricity. The anti-static precautions detailed in 2.1.
Anti-Static Precautions must be taken.
(e)
On the RAMP4 card, change over jumper 1-B-2 from the 1-B
position to the B-2 position to disconnect the power supply from the
battery to the card.
(f)
Make a careful note of all plug and wiring connections to the
RAMP4 card before disconnecting them one by one.
(g)
To prevent confusion with the replacement card, make a note of
the serial number of the old card before it is removed from the
panel.
(h)
Remove the card retaining nuts and carefully remove the RAMP4
card.
(i)
Lay the replacement card alongside the removed card and set all
jumpers on the new card so that their positions are identical to
those on the removed card; refer to Fig 20.
(j)
Fit the replacement card into position on the back of the enclosure
door and secure in place by refitting the retaining nuts. Do not
overtighten the nuts.
(k)
Reconnect all wiring to the card. Do not use excessive force when
making connections.