AERCO XPC GATEWAY Communications - Manual (Page 50)

GATEWAY COMMUNICATIONS MANUAL
50
3.2.1.2 BMS Wiring Connections to XPC Port 1a
When the BAS being used is communicating via LonWorks with an SLTA, or BACnet PTP, an RS485-to-
RS232 converter will be required to connect the BMS to Port 1a of the XPC.
1. Refer to Figures 3-2 and 3-3 to locate the internal RS232 connector JP12 inside the wiring area of the
BMS.
2. If the AERCO RS232-to-RS485 Converter (part no. 124942) is used, the RS232 side of the converter
contains a connector that plugs directly into header connector JP12 in the BMS. However, If a third
party converter is used, connect the RS232 receive (RxD) and transmit (TxD) wire leads to the
internal RS232 connector (JP12) as shown in Figure 3-6. DO NOT connect the wire shield on this
side of the converter.
NOTE
If a third-party RS232-to-RS485 Converter is used, consult the
manufacturer’s instruction manual for signal polarity.
3. At the RS485 side of the converter (Figure 3-6), connect the wire leads as follows:
(a) Connect the TD B (+) terminal to the Net + terminal on XPC Port 1a.
(b) Connect the TD A (-) terminal to the Net - terminal on XPC Port 1a.
(c) Connect the GND terminal to the Shield terminal on XPC Port 1a.
RXD
TXD
GND
RS232
JP12
Net +
Net -
Shield
P
O
RT
1a
XPC GATEWAY
RS232-TO-RS485
CONVERTER
TXD
RXD
GND
GND
B (+)
A (-)
RED (+)
BLUE (-)
GREEN (GND)
RED
ORANGE
IMPORTANT
CHECK INPUT & OUTPUT
POLARITY ON CONVERTER
BEING USED
BMS
RS232 RS485
+12V
SEE CONVERTER
INSTRUCTIONS
(124958)
Figure 3-6. Port 1a Wiring Connections for BMS
NOTE
A BMS option is available with a built-in RS485-to-232 Converter (part no,
124943). Therefore, AERCO recommends that the internal RS232 be used.
However, the external RS232 port (DB9) can be used if necessary.
4. On the right side of the XPC Gateway Module, check to ensure that DIP switches 3 and 4 are set to
the ON (left) position.