Lochinvar Harmony - Manual (Page 5)

5
CONNECTING AN EXTERNAL SET POINT
(4-20mA EMS-CONTROL)
• The Harmony can take a 4-20mA signal from an Energy Manage-
ment System (EMS) or other signal source to change the set point
remotely (see pg. 28 for additional details).
• The signal must be a two-wire 4-20mA.
• A system sensor must be installed as described in the previous
section.
• The External Set Point must be set up correctly (see pg. 12). These
settings will allow the Harmony to read and monitor the system
temperature and also monitor the 4-20mA input to remotely adjust
the Harmony set point to the desired value.
• The Harmony can source the current for the 4-20mA input. It
provides an excitation voltage of 24VDC. If using the Harmony to
source the power, attach the (+) side of the 4-20mA input to the
Harmony EMS terminal marked +. Attach the (-) side of the 4-20mA
signal to the EMS terminal marked SIGNAL.
• If the EMS or other signal sources the current (provides the
excitation voltage), attach the (+) side of the 4-20mA input to the
Harmony EMS terminal marked SIGNAL. Attach the (-) side of the
4-20mA input to the EMS terminal marked SHIELD.
WIRING THE SHUTDOWN
• This feature can be used whenever it is desirable to turn off the
Harmony from a remote location or another controller.
• A typical use for this feature would be to turn off all boiler stages
when an EMS panel no longer requires heat in the system.
• When the Shutdown feature is enabled by closing a dry contact, all
active stages will immediately modulate down to low. They will
remain in low for 45 seconds and then turn off.
• If the System Output relay was active, it will remain active until the
System Delay is over, then it will also turn off.
• The Shutdown signal must be a dry contact only. No voltage can
be placed across the SHUTDOWN terminals.
• Bring the two wires from the dry contact to the terminals marked
SHUTDOWN- A3, A4.
WIRING THE SYSTEM PROVE
EMS INPUT
+
SIGNAL
SHIELD
Harmony Sources Current
24VDC Excitation Voltage
(+)
(-) EMS
Input
EMS Sourcing Current
EMS INPUT
+
SIGNAL
SHIELD
(+)
(-) EMS
Input
INSTINSTINSTINSTINST
ALLAALLAALLAALLAALLA
TIONTIONTIONTIONTION
INPUT WIRINGINPUT WIRINGINPUT WIRINGINPUT WIRINGINPUT WIRING
Dry Contact
Shutdown
Signal
TEMP
SHUTDOWN
NETWORK
SYSTEM
PROVE
T
+
S
INPUTS
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10