Nordic ATWC Series, Инструкция по установке и обслуживанию, Страница: 51 / 106

PRELIMINARY: 24-Sep-2021 Page 51 002536MAN-00
BACnet Interface
TABLE 19 - BACnet OBJECTS - CONTROL SIGNALS (READ/WRITE)
Name Data Type ID Property Description
SYSTEM_O Binary Value BV2 Present Value Switch to cooling mode. Inactive= HEATING , Active= COOLING
SYSTEM_Y1A Binary Value BV0 Present Value Demand for water heating or cooling (active is on)
BACnet_Units Binary Value BV9 Present Value Select the units to use for the BACnet objects
Note: object names may be subject to change without prior notice.
TABLE 20 - BACnet OBJECTS - OPERATION MODE Description (Read Only)
Name Data Type ID
Present
Value
Description
Operation Mode Analog Value AV5 - Integer value represents operating mode.
2 Hydronic heating
3 Hydronic cooling
11 Hydronic heating off
12 Hydronic cooling off
Note: Object is type Analog Value but value will always be an integer value.
Note: Objects may be subject to change without prior notice.
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 (left pin)
If connecting multiple units to one RS-485 connection point, connect the signal cable from the master building controller to the first
unit. Connect 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 connected (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 together. 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.