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2.5.6 Electrical connections, master / slave systems
The controller can be used as master or slave in master / slave
systems via the internal ECL 485 communication bus (2 x twisted
pair cable).
The ECL 485 communication bus is not compatible with the ECL
bus in ECL Comfort 110, 200, 300 and 301!
Terminal Description
Type
(recomm.)
30
Common terminal
31*
+12 V*, ECL 485 communication bus
32
B, ECL 485 communication bus
33
A, ECL 485 communication bus
Cable 2 x
twisted pair
* Only for ECA 30 / 31 and master / slave communication
Total cable length: Max. 200 m (all sensors incl. internal ECL 485
communication bus).
Cable lengths of more than 200 m may cause noise sensibility (EMC).
ECL 485 bus cable
Maximum recommended length of the ECL 485 bus is calculated like
this:
Subtract "Total length of all input cables of all ECL controllers in the
master - slave system" from 200 m.
Simple example for total length of all input cables, 3 x ECL:
1 x ECL
Outdoor temp. sensor:
15 m
3 x ECL
Flow temp. sensor:
18 m
3 x ECL
Return temp. sensor:
18 m
3 x ECL
Room temp. sensor:
30 m
Total:
81 m
Maximum recommended length of the ECL 485 bus:
200 - 81 m = 119 m
2.5.7 Electrical connections, communication
Electrical connections, Modbus
ECL Comfort 210: Non-galvanic isolated Modbus connections
ECL Comfort 296: Galvanic isolated Modbus connections
ECL Comfort 310: Galvanic isolated Modbus connections
26 | © Danfoss | 2017.05
VI.LG.H4.02
Operating Guide ECL Comfort 210/296/310, application A230