SECTION 7 - OPERATION
JOHNSON CONTROLS
109
Form 201.28-NM1.1
Issue date: 08/06/2021
7
Building automation system (BAS)
communications
There are three different ways the chiller communi-
cates to the BAS.
• Using board Native Communication protocol
• Using an E-Link Gateway
• Using an SC-EQ Communication Card
Using communications protocol
TB3 Port 1 Native BAS RS-485.
SW1 RS-485 Biasing Switch for Port. Set to ON if
chiller is in an End of Line position on the network.
U26 is the Port 1 RS-485 Driver Chip. It is
socketed to allow field replacement. RX1 and TX1 LEDs
illuminate to indicate Port 1 communications activity.
YVAA native communication setup
Native communication is applicable to three types of
protocols, they are BACnet, N2 and Modbus (RTU).
It requires IPU II Microboard (331-03478-101) and
software version Y.ACS.20.02 or later.
BACnet MS/TP setup port 1 (TB3)
To set up the BACNET MS/TP Port 1, complete the
following steps:
1. Connect the BACnet MS/TP Network to Port 1 on
the IPU II I/O Board.
2. Set up the YVAA Port 1 (P1) for BACnet Com-
munications as shown in Figure 27 on page 108.
To access the Port communication parameters:
1. Press the PROGRAM key once.
2. Enter password 5255.
3. Press the (ENTER) key to display the Port 1
(P1) settings.
Set the following parameters:
1.
multiplied by 100): set as required by network.
2.
(see 8).
3. P1 Protocol: set to BACNET (Default Setting).
4. P1 Manual MAC Address: set to 1
(Default Setting).
5. P1 Baud rate: set as required by network.
If not known set to AUTO.
6. P1 Parity: set to NONE (Default Setting).
7. P1 Stop Bits: set to 1 (Default Setting).
N2 Metasys setup port 1 (TB3)
1. Connect the N2 Network to Port 1 on the IPU II
I/O Board as shown in Figure 18 on page 104.
2. Set up the YVAA Port 1 (P1) for N2 Communica-
tions.
To access the communication parameters:
1. Press the PROGRAM key once
2. Enter password 5255
3. Press (ENTER) to display the Port 1 (P1)
settings.
Set the following parameters:
1.
2.
3. P1 Protocol: Set to N2
4. P1 Manual MAC Address: Set to 0-127 as
required by the parameters set in the BAS
network.
5. P1 Baud Rate: 9600
6. P1 Parity: None (Default Setting)
7. P1 Stop Bits1: (Default Setting)
The BACnet DE Instance (Device In-
stance) is determined by adding the [DE
MODIFIER AD-DRESS x 100] with the
DE MODIFIER OFFSET. That is, if the
desired DE Instance address is 5023, set
the DE Modier Address to 50, and then
set the DE Modier Oset to 23 (50 X
100 + 23 = 5023). DE Instances must be
limited to values between 1 and 4,194,303
and every device in the network must have
a unique Device Instance.
You must always cycle power to the mi-
croboard following port setting changes.
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