Option 8 Remote Setpoint: Modbus Header Temp Sensor & Modbus Setpoint Drive - Watts AERCO Benchmark BMK750 Operation And Service Manual

Benchmark with Edge [I]: Operation-Maintenance Manual
SECTION 7 – BOILER SEQUENCING TECHNOLOGY
Option 8 Remote Setpoint: Modbus Header Temp Sensor & MODBUS
7.3.8
Setpoint Drive
OPTION 8 Instructions: Remote Setpoint, Modbus Header Temp Sensor & Modbus Setpoint
Drive
HEADER TEMP SENSOR WIRING – ANY BOILER
Step 1:
MODBUS
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 shield to any SHLD terminal on the I/O Board.
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.
•
Connect 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.
HEADER TEMP SENSOR
Step 3: OPTION 8 CONFIGURATION
On All Boiler:
Main Menu → Advanced Setup → BST Cascade → Cascade
1. Go to:
•
Set the Unit Mode parameter to BST Client.
Main Menu → Advanced Setup → BST Cascade → Application
2. Go to:
•
Set the Unit Address parameter to the communication address of the unit.
OMM-0145_A99 • GF-218 •
MODBUS TRANSMITTER
Continued on next page
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9/18/2019
I/O BOARD
Configuration:
Configuration:
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