Yaskawa Z1000U HVAC Matrix Bypass - Manual (Page 365)

u Wiring Diagram for Multiple Connections
Figure C.3 explains the wiring diagrams for multiple connections using BACnet communication.
n MS/TP Interface
Figure C.3 shows typical “daisy-chain” RS-485 wiring. If the bypass is at the end of the network, the drain wire should not
be connected and should be insulated from touching other components or ground. Connect the drain wire to earth ground at
the controller only to avoid ground loops.
Note: The isolated ground (IG5) connection is optional but strongly recommended to avoid noise issues. Yaskawa recommends using Belden
cable 3106A or equivalent for BACnet operation.
CONTROLLER
(customer-supplied)
1
2
3
4
+
-
SHLD
Bypass Drive
S1
OFF
TB3
SHLD
TXRX-
TXRX+
IG5
1
2
3
4
Bypass Drive
S1
OFF
TB3
SHLD
TXRX-
TXRX+
IG5
ON
1
2
3
4
Bypass Drive
S1
SHLD
TXRX-
TXRX+
IG5
Bypass
Control
Board A2
Bypass
Control
Board A2
Bypass
Control
Board A2
TB3
COMMON
Figure C.3 Connection Diagram for Multiple Connections
Note: Turn on DIP switch S1 on the bypass that is located at the end of the network. If S1 is missing, then an external 120 ohm resistor must be
placed across terminals TXRX+ and TXRX-. All other slave devices must have this DIP switch set to the OFF position (or if S1 is missing,
no external resistor is used).
u Network Termination
The two ends of the BACnet network line have to be terminated with a 120 ohm resistor between the TXRX+ and TXRX-
signals. The bypass has a built in termination resistor that can be enabled or disabled using DIP switch S1. If a bypass is located
at the end of a network line, enable the termination resistor by setting DIP switch S1 to the ON position. Disable the termination
resistor on all slaves that are not located at the network line end.
Note: Some bypass controllers do not have DIP switch S1. If this is the case, then an external 120 ohm resistor must be placed across the
TXRX+ and TXRX- signals if the bypass controller is at the end of a network line.
C.3 Connecting to a Network
YASKAWA SIEP YAIZ1D 01A Z1000U HVAC MATRIX Drive Bypass Technical Manual 365
C
BACnet Communications