ABB AC 800M, Manual

Page: 143 / 200

Section 2 Installation Installing the SB821 External Battery Unit
3BSE036351-510 A 143
Installing the SB821 External Battery Unit
Use the following procedure to connect the external battery unit:
1. Mount the SB821 external battery unit at a suitable position on the DIN-rail.
2. For connecting the SB821 external battery unit, use the 2 m (2.2 yd) cable
TK821V020. Plug one end into the battery unit and the other into the external
battery supply socket of the PM8xx processor unit (see
Figure 2 on page 32).
3. In redundant CPU configuration containing two PM861/PM864/PM865
processor units, use also two SB821 battery units, one for each processor unit.
4. Due to the batteries being connected in parallel, it is necessary, when using the
external battery, to remove the internal battery from the PM8xx in order to
avoid reducing available memory back-up time.
Do not connect the TK821V020 cable until the AC 800M Controller has been
powered-up normally and the memory back-up function has been activated,
that is, the B(attery) LED flashes. If no normal power supply is connected to
the PM8xx processor unit, the CPU memory will immediately start to consume
battery power when the cable is connected.
Always install a fresh internal or external battery at the end of the installation
phase. The original battery is heavily utilized due to frequent blackouts during
system installation.