Option 6 Remote Setpoint: Direct Wired 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 6 Remote Setpoint: Direct Wired Header Temp Sensor & Modbus
7.3.6
Setpoint Drive
OPTION 6 Instructions: Remote Setpoint, Direct Wired Header Temp Sensor, Modbus Setpoint
Drive
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.
Step 1: HEADER TEMP SENSOR WIRING – ANY BOILER
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.
3. Connect the Header Temp Sensor to pins 2 and 3 of the Modbus Transmitter using
Shielded pair 18 - 22 AWG cable.
4. On the Modbus Transmitter, install a jumper wire between pins 1 and 2.
NOTES:
•
Polarity must be observed for the RS485 connections.
•
Ground the shield to any Shield terminal on the I/O Board (such as Terminal 3 or 8).
•
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.
OUTDOOR TEMP SENSOR
OMM-0145_A99 • GF-218 •
MODBUS TRANSMITTER
MODBUS TRANSMITTER
Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST
9/18/2019
I/O BOARD
I/O BOARD
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