JOHNSON CONTROLS
163
SECTION 10 – MAINTENANCE
Form 150.63-NM9
Issue date: 5/20/2021
10
BACnet and Modbus communications
Chiller data that can be read and modified using spe-
cific BACnet or Modbus Register Addresses; and the
data associated with the addresses, is outlined in the
following description:
ANALOG WRITE POINTS
This data can be read and modified using a BACnet
or Modbus network connection. The Modbus Register
Address for these points is 1025 + AV #.
BINARY WRITE POINTS
This data can be read and modified using a BACnet
or Modbus network connection. The Modbus Register
Address for these points is 1537 + BV #.
ANALOG READ ONLY POINTS
This data can be read using a BACnet or Modbus net-
work connection and can NOT be modified using this
connection. The Modbus Register Address for these
points is 513 + AI #.
BINARY MONITOR ONLY POINTS
This data can be read using a BACnet or Modbus net-
work connection and can NOT be modified using this
connection. The Modbus Register Address for these
points is 1281 + BI #.
See Table 35 for complete list of BACnet and Modbus
registers.
The latest data map information is listed
on the Johnson Controls Equipment In-
tegration website.
Communications data map notes
(See Table 35 on page 164)
1. IPU II based units are congured for Native BAC-
net MS/TP and Modbus RTU communications.
Microgateway or E-Link not required for these
two communication protocols.
2. BACnet Object Types: 0= Analog In, 1 =
Analog Out, 2= Analog Value, 3= Bina-
ry In, 4 = Binary Output, 5= Binary Value,
8= Device, 15 = Alarm Notication (0 through
127 are reserved ASHRAE Objects).
3. WC= Inches of water column; CFM = Cubic Feet
beforeMinute; FPM = Feet beforeMinute: PSI =
Lbs beforesquare inch; Pa = Pascals; kPa = Kilo-
pascals; PPM = Part beforeMillion; kJ/kg = Kilo-
joules beforeKilogram.
4. Water Cooled Scroll units use the same rmware
as Air Cooled Scroll units, ignoring Fan Control.