Bacnet Interface; Table 21 - Bacnet Objects - Control Signals (Read/Write); Table 22 - Bacnet Objects - Operation Mode Description (Read Only) - Maritime Geothermal Nordic PC Series Installation And Service Manual

BACnet Interface

The BACnet interface is an MS/TP connection via RS-485 twisted pair. Recommended wire: 22-24 AWG single twisted pair, 100-
120 Ohms impedance, 17pF/ft or lower capacitance, with braided or aluminum foil shield, such as Belden 9841 or 89841.
The connector on the control board is a three wire removable screw connector. The signals are as follows:
A: Communications line (+) (right pin)
B: Communications line (-) (middle pin)
C: Ground connection
If connecting multiple units to one RS-485 connection point, connect the signal cable from the master controller to the first unit. Con-
nect the second unit to the first unit (in same connector), connect the third unit to the second unit, and so on until all units are connect-
ed (daisy-chain). Remove the TERM jumper (located just above the BACnet connector on control board) from all units except the last
one. The shield ground should be connected only to the GND pin of the unit for single unit installations. For multiple units, the shield
ground should only be connected to the GND pin of the last unit. The shield grounds for intermediate units should be connected to-
gether. The shield ground should be left unconnected at the building controller end for all cases.
Vendor: Maritime Geothermal Ltd.
Vendor ID: 260
Model Name: MGT GEN2 Control Board
The following parameters can be set via the PC APP Configuration Page:
1) Baud rate
2) MAC address
3) Instance number
The data is available regardless of the selected control method. In order to control the unit via the BACnet interface, set the Control
Source to BACnet either by using the PC APP configuration page or the display menus.
The following tables provide a list of the objects applicable to this model series, along with a description of each.
Note that there may be other objects available that do not apply to this model.

TABLE 21 - BACnet OBJECTS - CONTROL SIGNALS (READ/WRITE)

Name Data Type
SYSTEM_Y1 Binary Value
SYSTEM_O Binary Value
SYSTEM_DH Binary Value
SYSTEM_Y1A Binary Value
SYSTEM_G Binary Value
BACnet_Units Binary Value
Note: object names may be subject to change without prior notice.

TABLE 22 - BACnet OBJECTS - OPERATION MODE Description (Read Only)

Name Data Type
Operation Mode Analog Value
Note: Object is type Analog Value but value will always be an integer value. Objects may be subject to change without prior notice.
ISSUE 03: 1-Oct-2021
(left pin)
ID Property
BV3 Present Value Air heat or air cooling demand
BV2 Present Value Switch from air heat to cooling. Inactive=HEATING,
BV7 Present Value Air dehumidify demand
BV0 Present Value Pool water heat demand
BV6 Present Value Fan recirculation (active is on)
BV9 Present Value Select the units to use for the BACnet objects
ID Present Value
-
1
6
7
9
AV5
18
20
22
23
24
Integer value represents operating mode.
Air Cooling
Air Reheat
Pool Heat
OFF
Air Cooling with DH demand
Air Reheat with DH demand
Pool Heat with AC demand
Pool Heat with DH demand
Pool Heat with AC and DH demands
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Description
Active=COOLING
Description
002291MAN-03