Bus For Connection To An Rs485 Modbus Cms; Bus Connection Between The Units And The Cms - Carrier CCU Control Manual

13 - BUS FOR CONNECTION TO AN RS485 MODBUS CMS

13.1 - Bus connection between the units and the CMS

The communication bus between the units and the CMS is a 2-wire RS485 bus
The green light indicates that the data sent by the CMS to the CCU CONTROLLER has been received.
The yellow light indicates that data has been sent by the CCU CONTROLLER to the CMS.
Intermediate unit(s)
Last unit
COM1: Line termination resistor switch
- First unit = OFF
- Intermediate unit = OFF
- Last unit = ON
70
1st Unit
ON
J10
OFF
1 2 3
COM1
ON
J10
OFF
1 2 3
COM1
ON
J10
OFF
1 2 3
COM1
To CMS
Multiconductor cables, shielded,
jacketed (shielding with braiding)
length between the 1st and the
l a s t C C U C O N T R O L L E R :
1000 m
1: Line A or +
2: Line B or -
3: Earth
To ensure correct operation, the
line must be polarised.
Multiconductor cables, shielded,
jacketed (shielding with braiding)
length between the 1st and the
l a s t C C U C O N T R O L L E R :
1000 m
1: Line A or +
2: Line B or -
3: Earth