Option 7 - Remote Setpoint With Modbus Header Sensor And 4-20Ma Setpoint Drive - Aerco BENCHMARK 2500DF User Manual

Dual fuel gas-fired boiler
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CHAPTER 10. BOILER SEQUENCING TECHNOLOGY
10.3.7 Option 7 - Remote Setpoint with MODBUS Header Sensor AND 4-20ma
Setpoint Drive
NOTE: Both Header Sensor AND 4-20ma Direct Drive must be wired. See the C-More Controller User
Manual, OMM-0032, GF-112 and ProtoNode User Manual, OMM-0080, GF-129 for more information.
Step 1: MODbus Header Sensor
1. Using Shielded pair 18 - 22 AWG cable, Connect the Temperature Transmitter (AERCO P/N 65169)
terminal Pin B to the RS485+ terminal on the I/O Box of any of the Boiler units, and Pin A of the
Temperature Transmitter to the RS485- terminal on the I/O Box of any of the Boiler units.
2. Using Shielded pair 18 - 22 AWG cable, connect the Modbus Header Temperature Sensor (AERCO
PN 24410) to pins 2 and 3 of the Temperature Transmitter.
3. Install a jumper wire between pins 1 and 2 of the Temperature Transmitter.
NOTES:
Polarity must be observed for the RS485 connections. The ground for the shield is at the "SHLD"
terminal in the I/O the Box.
The header sensor must be installed between 2 and 10 feet 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.
Temp Sensor PN 24410
Step 2: Direct Wired 0-20ma or 4-20ma Wiring
1. Connect the 4-20ma or 0-20ma terminals from the Direct Drive source to the Ain+ and Ain- terminals
on the Master.
NOTES:
Unit's I/O Box. Shielded pair 18 - 22 AWG cable is recommended for this connection. Polarity must
be observed.
The ground for the shield is at the driver signal source.
OMM-0099_0A
GF-145
Benchmark 2500DF-3000DF
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913
Ph.: 800-526-0288
Modbus Transmitter
I/O Box
Page 135 of 234
PR1: 05/21/2014

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