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Benchmark 2500DF-3000DF Installation, Operation & Maintenance Manual
signal is equal to a 40°F setpoint while a 20 mA /5V signal is equal to a 240°F setpoint. When a 0 to 20
mA/0 to 5 VDC signal is used, 0 mA is equal to a 40°F setpoint.
In addition to the current and voltage signals described above, the Remote Setpoint mode can also driven
by a RS485 Modbus Network signal from an EMS or BAS.
The Remote Setpoint modes of operation can be used to drive single as well as multiple units.
If a voltage, rather than current signal is used to control the
remote setpoint, a DIP switch adjustment must be made on the
PMC Board located in the Control Panel Assembly. Contact your
local AERCO representative for details.
In order to enable the Remote Setpoint Mode, the following menu setting must be made in the
Configuration Menu:
Menu Option
Boiler Mode
Remote Signal
Refer to section 3.3 for detailed instructions on changing menu options.
If the Network setting is selected for RS485 Modbus operation, a valid Comm Address must be entered in
the Setup Menu. Refer to Modbus Communication Manual GF-114 for additional information.
While it is possible to change the settings of temperature related functions, the unit is factory preset with
settings that work well in most applications. It is suggested that an AERCO representative be contacted,
prior to changing any temperature related function settings. For descriptions of temperature-related
functions and their factory defaults, refer to Appendices A and E.
5.4.1 Remote Setpoint Field Wiring
The only wiring connections necessary for the Remote Setpoint mode are connection of the remote signal
leads from the source to the unit's I/O Box. The I/O Box is located on the front panel of the boiler. For
either a 4-20mA/0-5V or a 0-20mA/0-5V setting, the connections are made at the ANALOG IN terminals
in the I/O Box. For a Network setting, the connections are made at the RS-485 COMM terminals in the I/O
Box. The signal must be floating, (ungrounded) at the I/O Box and the wire used must be a two wire
shielded pair from 18 to 22 AWG. Polarity must be observed. The source end of the shield must be
connected at the source. When driving multiple units, each unit's wiring must conform to the above.
5.4.2 Remote Setpoint Startup
Since this mode of operation is factory preset and the setpoint is being externally controlled, no startup
instructions are necessary. In this mode, the REMOTE LED will light when the external signal is present.
To operate the unit in the Manual mode, press the AUTO/MAN switch. The REMOTE LED will go off and
the MANUAL LED will light.
To change back to the Remote Setpoint mode, simply press the AUTO/MAN switch. The REMOTE LED
will again light and the MANUAL LED will go off.
OMM-0099_0A
GF-145
CHAPTER 5 – MODE OF OPERATION
NOTE
Setting
Remote Setpoint
4-20mA/1-5V, 0-20mA/0-5V, or Network
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913
Ph.: 800-526-0288
Page 71 of 234
PR1: 05/21/2014
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