Memory; Rs485 Wiring Recommendations - ADEMCO Galaxy 16 Engineer's Manual

RS485 Recommendations

RS485 Wiring Recommendations

To ensure that the system communicates at the maximum level of efficiency the
following recommendations must be adhered to:
1. It is strongly recommended that the system is wired in a daisy-chain
configuration. That is, the A terminal from the previous module is
connected to the A terminal of the current module and then on to the A
terminal of the next module. The B line should be connected in the same
manner. Spur and star configurations should not be used as they reduce
immunity to electrical interference.
2. The cable used to wire the AB line should be screened, twisted pair
(Belden equivalent 8723) Part No. W002.
3. Screened, twisted pair cable, where used, is connected to ground (0 V)
only at the P-clip in the control panel enclosure, see Figure 1.8 P-Clip
Connection.
4. The AB line must have a 680 Ω End-of-Line (EOL) resistor fitted across
the A and B terminals of the last module on the line. If two runs are
connected, both ends must be terminated with 680 Ω (EOL) resistors
and R38 on the control panel PCB must be cut, see Figure 1.7 Twin AB
Line Daisy Chain Configuration.
5. The power supply in the Galaxy control panel and remote power
supplies must not be connected in parallel. The 0 V of all remote power
supplies should be connected in common to the 0 V of the Galaxy
control panel.

Memory

The Galaxy 16 and 16 plus control panels are fitted with a Non Volatile Memory
(NVM) chip. This allows the panels to retain programming details when both
the mains power and stand-by battery have been disconnected. The NVM can
be transferred from a Galaxy 16 or 16 plus to another without loss of program-
ming.
Note: On swapping NVMs between a Galaxy 16 and 16 plus it is strongly
recommended that the programming is restored to the factory defaults
using the Cold Start parameter, refer to
Option 6 – Parameters; 9 Cold Start
AB connectors
A
data line
RS 485 cable
Cable screen
Nut
P-clip
P-clip
Earthing pillar
(threaded)
Figure 1.8 P-Clip connection.
8
B
data line
Section 5: MENU OPTIONS;
.