AERCO XPC GATEWAY Communications - Manual (Page 89)

GF-122 AERCO XPC GATEWAY
89
NOTE
See SECTION 16 for the BACnet Protocol Conformance Statement.
14.3 BACNET MS/TP
1. Both set to speak BACnet MS/TP.
• Comm Selector DIP switches 5, 6, 7, and 8
• Both set to speak BACnet MS/TP.
2. Both set for the same baud rate.
• Comm Selector DIP Switches 1 and 2
• Verify by obtaining a Modstat
3. BAS configured to speak 2—wire EIA--485 to the translator.
4. Both set to 8 data bits, No Parity, and 1 stop bit.
5. Rotary address switches set for the translator’s unique slave address.
6. Proper connection wiring.
7. BAS reading or writing to the proper BACnet objects in the translator - download the latest points list
for the translator to verify.
8. BAS is sending requests to the proper MS/TP MAC address of the translator.
9. Present the BAS company with a copy of your translator's BACnet PICS so that they know which
BACnet commands are supported.
It may be necessary to adjust the following two MS/TP Protocol timing settings.
1.
Max Masters - defines the highest MS/TP Master MAC address on the MS/TP network.
For example, if there are 3 master nodes on an MS/TP network, and their MAC addresses are 1, 8,
and 16, then Max Masters would be set to 16 (since this is the highest MS/TP MAC address on the
network).
This property optimizes MS/TP network communications by preventing token passes and “poll for
master” requests to non—existent Master nodes
In the above example, MAC address 16 would know to pass the token back to MAC address 1
instead of counting up to MAC address 127). Each MS/TP master node on the network must have
their Max Masters set to this same value. The default is 127.
2.
MaxInfo Frames -
defines the maximum number of responses that will be sent when the translator
receives the token. Any positive integer is a valid number. The default is 10 and should be ideal for
the majority of applications. In cases where the translator is the target of many requests, this number
could be increased as high as 100 or 200.
It should be noted that:
• MS/TP networks can be comprised of both Master and Slave nodes. Valid MAC addresses for
Master nodes are 0 – 127 and valid addresses for Slave nodes are 0 -- 254.
• See Protocol Maps in SECTION 29.