Reset button
The SNC features a recessed Reset button that is located
directly above the LEDs and to the left of the Recovery
button. To force an immediate restart of the SNC engine
and a reset of the processor, press and hold down the
Reset button for at least four seconds with an extended
paper clip or mini screwdriver. This action is otherwise
known as a hard reset or processor reset. During the
reset, the SNC's archive database and any data the SNC
has collected are lost. The data includes all historical
information, including alarm, trend, and audit trail
data. If you need to reset the SNC but retain the archive
and stored historical data, you can either press and
immediately release the reset button, or issue a Reset
Device command from the user interface. This type of
reset is known as a soft reset.
Note:
Press the reset button only if the SNC fails to
respond and users cannot access it. Do not press the
reset button unless you have tried other means to
fix the problem.
Recovery button
The SNC features a recessed Recovery button that is
located above the LEDs and to the right of the Reset
button. Use the Recovery button to restore device
functionality. To place the SNC into recovery mode, press
and immediately release the Recovery button with an
extended paper clip or mini screwdriver. Use the Recovery
operation under these conditions:
• the current password is unknown
• the device is rebooting continuously
• the device is unresponsive or is in a frozen state
• the device fails to take a code download from SCT
Important:
If you are unsure about whether to use
the Recovery operation, contact Johnson Controls
technical support.
When you press the Recovery button, the action that
takes place depends on whether this is the first time or
a subsequent time you pressed the button. The actions
taken are as follows:
•
First press (odd-numbered)
: The SNC resets and
restores the factory default settings on the active
partition.
•
Second press (even-numbered)
: The SNC resets
and makes the opposite partition the currently active
partition with the factory default settings. Any staged
configuration files are lost. If the SNC has never been
imaged with a release other than the shipped factory
release, then both partitions (active and inactive) are
now at the same release. Once the SNC is imaged in
the field with a release other than the factory release,
the active and inactive partitions are at different
releases. At this point, it is your responsibility to verify
the SNC's active partition is at the correct release. If it
is not, you need to download the SNC with the correct
code from SCT.
This process repeats the next time the Recovery button
is pressed with the exception of each time an SCT code
download is performed, which resets the Recovery button
back to the default setting.
The differences between the two states are further
Notes:
• To determine which partition is currently active, open
the FX SMP UI in Expert mode and locate the Update
object of the SNC under All Items - Expert tab. The
Active System Partition attribute is visible under
the Focus window of the Update object as either A
(Partition 0) or B (Partition 1).
• After you press the Recovery button, allow time for
the SNC to restart
before
you press the button again.
Pressing the button twice in fast sequence equates to
pressing the button only once.
• The firmware version in the inactive partition may be
older than the version in the active partition, and may,
in fact, lack security enhancements that are present in
the newer, active partition.
• If the system partition to which you are switching is
corrupt, the operating system loader does not switch to
the defective partition, but instead keeps the currently
active partition in place.
F4-SNC Installation Guide
19