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For Dipswitch SW1 configuration of primary and secondary panel see
Settings. for further advanced software settings, see Chapter of the MPA2C3 user
manual.
Figure 3-33 Downstream Panel Connections of RS-485 Bus
The RS-485 Downstream bus is wired from the RJ45 DOWNSTREAM RS485 OUT
terminal to the blue RJ45 DOWNSTREAM RS485 IN terminal.(Preferably use CAT
6E/7 S/FTP cable). Use pin1&2 (TA/TB) to connect the downstream panels. Make
sure the downstream panels are powered by their local power supply.
RS485 Bus Termination.
An RS485 bus must be terminated with a resistor at both ends of the RS-485 bus.
If the MPA2C3 panel is at the beginning or end of the Downstream RS485 bus,
then the bus must be closed with 120 Ohm resistor. On Dipswitch SW3 both bit 7
and 8 (EOL DNSTRM) must be set to ON position to add the resistor to the RJ45
DOWNSTREAM RS485 IN and OUT communication wires.
External I/O Devices via RS-485
Note: UL has not evaluated the compatibility I/O devices with the MPA2C3 panel.
Note: At the time of the launch of the MPA2C3, the NX4IN and NX4OUT modules were
made obsolete. Use this section as reference for backward compatibility.
In some applications, the number of system inputs or outputs exceeds the number
that is standard on the panel. The solution is to add a combination of NX4IN and
NX4OUT downstream I/O devices as external devices to the MPA2C3 enclosure,
which are connected to the panel via a dedicated RS-485 interface bus. A maxi-
mum of 2 NX4IN and maximum of 2 NX4OUT for a total of 2 downstream I/O
devices can be added to the downstream bus.
A NX4IN module has 32 supervised, 4-state inputs that are limited to 2.2K Ohms
resistance. The NX4OUT has 2 supervised inputs and 16 SPDT relay outputs; each
input is limited to 2.2K Ohms resistance. Refer to the individual installation manu-
als for I/O wiring details.
MPA2C3 Installation Guide
DIP Switch
97
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