Chapter 10 BCU Operation and Communication Status
204 BMTW-SVN01F-EN
Clear BCU RAM and Reset
The BCU normally preserves the content of RAM through power failure.
RAM contains the current status of all BCU object trend data, events,
and alarms. In most cases, this is desirable. However, there are circum-
stances in which you may need to clear RAM. This is normally done from
the PC Workstation, as described in the System Programming guide.
RAM can also be cleared at the BCU as follows:
1. Turn off power to the BCU.
2. Set all DIP switches to on.
3. Turn on power.
4. The LED display should show 8, then E, and then E with the decimal
point flashing.
CAUTION
If you wait longer than 10 seconds, the BCU code and database may be
cleared as well as its RAM.
5. As soon as the LED display shows E with the decimal point flashing,
turn off power.
6. Set the DIP switch to its proper position.
7. Turn on power. The LED display should show the following sequence:
8, 7, 6, 5, 4, 3, 2, 1, “dancing dash”
Clear Database, RAM, and Reset
Database contains the user programmed data, which consists of all BCU
objects, such as areas, VAVs, I/O, UCMs, trends, CPL, etc. See the defini-
tion of RAM in “Clear BCU RAM and Reset”.”
In most cases, you will perform this operation from the PC Workstation,
as described in the System Programming guide. However, this can also be
done at the BCU as follows:
1. Change the DIP switch S2 position 8 to Off.
2. The LED display will show the following sequence:
J, 8, 7, 6, 5, 4, 3, 2, 1, –, P
3. Change DIP switch S2 position 8 back to on.
4. The LED display will show the following sequence:
J, 8, 7, 6, 5, 4, 3, 2, 1, –, P
Note:
When the BCU has code and detects a change in DIP switches
at S2, the BCU clears the current database and looks for a PC
Workstation from which to download a database that matches
the new device ID (corresponding to the settings at DIP switch
S2).
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