Danfoss ECL Comfort 310 Посібник з експлуатації - Сторінка 4

Service guide

5.0 ECL 296 / 310 Modbus network specification

The ECL 296 / 310 Modbus physical layer interface is supported by

the half duplex RS485 interface (A, B, common signal - i.e ref GND).

1. Maximum trunk (Bus) length = 1200 meters for AWG24

(0,51mm diameter) copper (less AWG= bigger diameter: is bet-

ter).

Note: AWG= American wire gauge (AWG).

2. Maximum number of nodes in the network = 32 (including

master node, ECLs and repeater node).

Note: Each repeater node is capable of driving another 32

nodes (including repeater node) of 1200 meter.

I.e. 30 ECLs between two repeater stations (or) 31 ECLs in the

network connected to master node / repeater node. Refer the

figure below.

3. Maximum derivation cable length per node (per ECL) = 1,25

meters (calculated based on 40 m max. derivation cable length

for 32 nodes).

4. Line termination (to ensure the communication quality) = At

each extremity of the trunk cable (150 ohms (or) 120 ohms, 0,5

watts resistor at both ends.

Note: Repeaters are having internal termination resistors which

can be "switched on/ switched OFF" by the user.

If "repeaters" are used in the extremity of the trunk cable, then

switch on the repeater termination (striped block, represented

by 3):

If "repeaters" are used to make a branch from one of the interme-

diate nodes, then do not switch on the "repeater termination"

(unstriped block connected to ITr cable).

If the ECL is used in the extremity node of the trunk cable, connect

an external line termination (150 ohm / 120 ohm, 0,5 watts resis-

tor).

ECL 296 / ECL 310 Modbus

1) = surge protector

2) = repeater

3) = line termination (LT)

VI.LV.H1.02