LAARS NeoTherm NTV1000 - Install and Operating Manual - Manual (Page 70)

LAARS Heating Systems
Page 66
fig. 81 – modbus Connections
Boiler 1
Ctrl
1
Ctrl
2
A B C
MB 2 MB 1 MB 2 MB 1
A B C
Boiler 2
Ctrl
1
Ctrl
2
A B C
MB 2 MB 1 MB 2 MB 1
A B C
Boiler 3
Ctrl
1
Ctrl
2
A B C
MB 2 MB 1 MB 2 MB 1
A B C
Boiler 4
Ctrl
1
Ctrl
2
A B C
MB 2 MB 1 MB 2 MB 1
A B C A B C A B C A B C A B C A B C A B C A B C A B C A B C
Display
9 8 7 6 5 4 3 2 1
B A C B A C B A C
MB1 MB2
R1
Display
MB1 connections -
Do not change
Disconnect
the wires from
MB2 to the
display
fig. 80 – Disconnecting an Unused operator
Interface
Job H - Connect the modbus Wiring
(This is an individual function – do this on each of the controls.)
In an installation with multiple boilers, the controllers
are arranged in a “daisy chain.” The wiring from
the Secondary controller on one boiler runs to the
Primary controller on the next boiler. Use 22 AWG
or thicker shielded twisted pair wire with drain. Two
twisted pairs or three conductors are needed.
note – The Modbus wiring should be done last. The
controllers must be set up and addressed correctly
before the wiring is complete. If the wiring is attached
before the Modbus addresses for the controllers are
set up, there might be multiple controls with the same
address, and the system will not work.
1. Connect the wiring from the Secondary
controller on Boiler 1 to the Primary controller
on Boiler 2. Connect three wires from the
Modbus 1 terminal (MB1 on J3) on the
Secondary control on Boiler 1 to MB1 (also
MB1 on J3) on the Primary control on Boiler 2.
Wire A on Boiler 1 must be connected to A on
Boiler 2, wire B on Boiler 1 goes to B on Boiler
2, and wire C on Boiler 1 goes to C on Boiler 2.
2. Repeat this wiring from Boiler 2 to Boiler
3, and from Boiler 3 to Boiler 4 if additional
boilers are included. A maximum of 4 boilers or
8 controls can be connected this way.
3. Another part of the “daisy chain” connection
uses the MB2 connectors. Connect three wires
from the Modbus 2 terminal (MB2 on J3) on
the Secondary control on Boiler 1 to MB2 (also
MB2 on J3) on the Primary control on Boiler
2. Be sure that wire A on Boiler 1 goes to A on
Boiler 2, wire B on Boiler 1 goes to B on Boiler
2, and wire C on Boiler 1 goes to C on Boiler 2.
4. Repeat this wiring from Boiler 2 to Boiler
3, and from Boiler 3 to Boiler 4 if additional
boilers are included.
5. Connect the drain wire from each twisted pair
wire to ground on one end of each wire only.
Job I – Set the Parameters Used by the
lead/lag System
(This is a Lead/Lag function – do this once for the whole Lead/
Lag system. Use the controller set up as the Lead/Lag Master –
usually the Primary controller on Boiler 1.)
We have already explained how the Lead/Lag Master
controls the operation of the Lead/Lag system. Your
job at this point is to enter the control values that the
Lead/Lag system will use.