Option 4 Outdoor Reset: Modbus Header Temp Sensor & Modbus Outdoor Temp Sensor - Watts AERCO Benchmark BMK750 Operation And Service Manual

Benchmark with Edge [I]: Operation-Maintenance Manual
SECTION 7 – BOILER SEQUENCING TECHNOLOGY
Option 4 Outdoor Reset: Modbus Header Temp Sensor & Modbus Outdoor
7.3.4
Temp Sensor
OPTION 4 Instructions: Outdoor Reset, Modbus Header Temp Sensor & Modbus Outdoor
Temp Sensor
NOTE:
Both Header Temp Sensor and Outdoor Sensor must be wired. See the Edge [i] Controller
Manual (OMM-0141, GF-213-B) for more information.
ep 1: HEADER TEMP SENSOR WIRING – ANY BOILER
St
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 (P/N 61040) 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.
HEADER TEMP SENSOR
Step 2: OUTDOOR SENSOR WIRING
1. If you have not already done so, complete step 1 of the instructions above to connect the
Modbus Transmitter to the I/O Board.
2. Connect the Outdoor Temp Sensor to Pins 5 and 6 of the Modbus Transmitter using a
shielded pair 18 - 22 AWG cable.
3. On the Modbus Transmitter, install a jumper wire between Pins 4 and 5.
OMM-0145_A99 • GF-218 •
MODBUS TRANSMITTER
Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST
9/18/2019
I/O BOARD
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