Benchmark 2.0 LN Installation, Operation & Maintenance Manual
CHAPTER 5 – MODE OF OPERATION
Page
66
of
168
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
OMM-0046_0J
06/18/2015
Phone: 800-526-0288
GF-123
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.
5.5 DIRECT DRIVE MODES
The unit’s air/fuel valve position (% open) can be changed by a remote signal which is typically
sent from an Energy Management System (EMS) or from a Building Automation System (BAS).
The Direct Drive mode 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 Direct Drive mode is 4-20 mA/1-5 Vdc. With this setting, a 4
to 20 mA signal, sent by an EMS or BAS is used to change the unit’s valve position from 0% to
100%. A 4 mA/1V signal is equal to a 0% valve position, while a 20 mA /5V signal is equal to a
100% valve position. When a 0-20 mA/0-5 Vdc signal is used, zero is equal to a 0% valve
position.
In addition to the current and voltage signals described above, the Direct Drive mode can also
driven by a RS485 Modbus Network signal from an EMS or BAS.
When in a Direct Drive mode, the unit is a slave to the EMS or BAS and does not have a role in
temperature control. Direct Drive can be used to drive single, or 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 PMC Board
located in the Control Box Assembly. Contact your local AERCO
representative for details.
To enable the Direct Drive Mode, the following menu setting must be made in the Configuration
Menu:
MENU OPTION
SETTING
Boiler Mode
Direct Drive
Remote Signal
4-20mA/1-5V,
0-20mA/0-5V, or
Network
Refer to paragraph 3.3 for instructions on changing menu options.
