Benchmark with Edge [I]: Operation-Maintenance Manual
SECTION 7
– BOILER SEQUENCING TECHNOLOGY
OMM-0145_A99
• GF-218 • 9/18/2019 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST Page
109
of
157
7.3.2
Option 2 Constant Setpoint: Modbus Wired Header Temp Sensor
OPTION 2
Instructions: Constant Setpoint with Modbus Wired Header Temp Sensor
Step 1: MODBUS HEADER TEMP SENSOR WIRING
– ANY BOILER
Using the Modbus Transmitter provides gives the plant the ability to use the Backup
manager feature. This allows the any of the client units to become a Backup manager if
the manager unit is not communicating.
1. Connect the
Modbus Transmitter
terminal
Pin B
to the
RS485+
terminal, and
Pin A
to
the
RS485-
terminal on the I/O Board of any Boiler unit, using shielded pair 18 - 22 AWG
cable.
2. Connect the
Header Temp Sensor
to pins
2
and
3
of the
Modbus Transmitter
using
shielded pair 18 - 22 AWG cable.
3. Install a jumper wire between pins
1
and
2
of the
Modbus Transmitter
.
NOTES:
•
Polarity must be observed for the RS485 connections.
•
Ground the shield to any
SHLD
terminal on the I/O Board.
•
The
Header Temp Sensor
must be installed between 2 and 10 feet (0.61 and 3.1m)
downstream of the
last
boiler in the plant’s supply water header.
•
There is no polarity to be observed. The ground for the shield is at the power supply
ground. The sensor end of the shield must be left free and ungrounded.
Step 2: OPTION 2 CONFIGURATION
On All Boiler:
1. Go to:
Main Menu
→
Advanced Setup
→
BST Cascade
→
Cascade Configuration
:
•
Set the
Unit Mode
parameter to
BST Client
.
2. Go to:
Main Menu
→
Advanced Setup
→
BST Cascade
→
Application Configuration
:
•
Set the
Unit Address
parameter to the communication address of the unit.
Continued on next page
MODBUS TRANSMITTER
HEADER TEMP SENSOR
I/O BOARD
