Modbus Communications - HydroTherm HeatNet KN -6 User Information

MODBUS COMMUNICATIONS

MODBUS Communications
The KN-Series control can be controlled using Modbus commands to Enable/Disable the boiler/system. A connection to the
Console Modbus Port on the Communications board is required. The Master Boiler assumes the role of MEMBER, RTU, 192Kb,
8 bits, Even Parity, 1 stop bit, when connected to a BMS (Building Management System).
The Member Boilers should not be connected to a BMS system other than to view Read Only addresses. Refer to
http://www.knseries.com/
Boiler01 = The Modbus connected boiler (Master or Standalone)
Boiler02 = Member 2
Boiler03 = Member 3
...
Boiler16 = Member 16
Address Name
40001 HeatDemand
40002 SetpointTimer
40003 Setpoint
40004 OAResetEnable
40005 OARSetpoint
40006 OARHighWaterTemp
40007 OARHighAirTemp
40008 OARLowWaterTemp
40009 OARLowAirTemp
40010 SetMonth
40011 SetDay
website for greater detail on communicating with Modbus, BACnet, or LonWorks protocols.
Figure 40 MODBUS Input/Output Variables (Read/Write)
Raw Data Type
1 bit unsigned
16 bit unsigned
8 bit unsigned
1 bit unsigned
8 bit unsigned
8 bit unsigned
8 bit unsigned
8 bit unsigned
8 bit signed
8 bit unsigned
8 bit unsigned
Scale Description
Heat Demand/Request. Setting the state
--- member of this variable will put the boiler
in heating mode.
System Setpoint Timer
The system setpoint timer and system
setpoint work in tandem to externally
control (i.e. a BMS - building management
system) the operating setpoint. The
setpoint (countdown) timer should be
loaded with a timeout value (in seconds)
--- prior to writing the system setpoint. When
the timer reaches zero, the control assumes
that the BMS is no longer operating and the
local setpoint (saved on the control) is
reloaded. This is a failsafe feature used to
help safeguard the system in case of BMS
failure. If the setpoint timer is not written,
a default timeout value of 60 seconds is
assumed.
1.0 System Setpoint (see SetpointTimer)
--- Enables/Disables outdoor air reset mode.
Outdoor air reset setpoint. Temperature at
1.0
which boiler shuts down.
Boiler water temperature setpoint when
outdoor air temperature is at the high
1.0
outdoor air temperature setpoint
(OARHiAirTemp).
1.0 High outdoor air temperature setpoint.
Header/Supply temperature setpoint when
outdoor air temperature is at the low
1.0
outdoor air temperature setpoint
(OARLoAirTemp).
1.0 Low outdoor air temperature setpoint.
Set real time clock – month (see SetClock)
---
Set real time clock – day (see SetClock)
---
HeatNet Control V3 2.x
Valid Values/Range
0 = no heat demand
1 = heat demand
0 – 65535 seconds
40 - 220 °F
0 = disabled
1 = enabled
40 – 100 °F
60 – 190 °F
50 – 90 °F
70 – 220 °F
-35 – 40 °F
0 (January) - 11
(December)
1 – 31
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