AERCO BMK 1.5 LN Dual Fuel Feb 2013 - Manual (Page 61)

CHAPTER 5: MODE OF OPERATION
PR2: 05/09/12 Page 61 of 162
Benchmark 1.5LN Dual-Fuel Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0C
GF-121
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
5.4 REMOTE SETPOINT MODES
The unit’s setpoint can be remotely controlled by an Energy Management System (EMS) or
Building Automation System (BAS). The Remote Setpoint can be driven by a current or
voltage signal within the following ranges:
• 4-20 mA/1-5 VDC
• 0-20 mA/0-5 VDC
The factory default setting for the Remote Setpoint mode is 4 - 20 mA/1 - 5 VDC. With this
setting, a 4 to 20 mA/1 to 5 VDC signal, sent by an EMS or BAS, is used to change the
unit's setpoint. The 4 mA/1V 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.
NOTE
If a voltage, rather than current signal is used to
control the remote setpoint, a DIP switch adjustment
must be made on the CPU 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
SETTING
Boiler Mode Remote Setpoint
Remote
Signal
4-20mA/1-5V,
0-20mA/0-5V, or Network
Refer to paragraph 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.
Remote Setpoint Field Wiring 5.4.1
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