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BACnet instance calculator · SDV5 VRF BACnet gateway GW-BAC
Sinclair SDV5 GW-BAC BACnet Device ID Calculator
Free browser tool · nothing is uploaded · 5 November 2026
The Sinclair GW-BAC makes every SDV5 indoor and outdoor unit its own BACnet device. Its device instance comes from the gateway's network number, the RS-485 port and the unit address.
Indoor unit device instance = network number x 10000 + port x 1000 + indoor address; outdoor units add 100 to the address. Network 2, port 1, indoor unit 7 is 21007; outdoor unit 3 on the same port is 21103. Every indoor unit device has the same object instances.
Sinclair calculator
The calculator needs JavaScript. The formula and a worked example are below.
Which unit is this device?
How the numbers are built
device = network x 10000 + port x 1000 + address (outdoor + 100)
| Part | Meaning | Range |
|---|---|---|
| network | BACnet network number set on the gateway's web page | 2-254 |
| port | RS-485 port (0 = the one next to the Ethernet jack) | 0-3 |
| address | Indoor unit address (outdoor: 100 + outdoor address) | 0-63 (OU 0-31) |
Set a BACnet network number of 2-254 that nothing else uses on the gateway's web page, then restart it. Ports are numbered 0-3, port 0 being the one next to the Ethernet jack.
Worked example: network 2, port 1, indoor unit 7
The first objects for network 2, port 1, indoor unit 7 on the GW-BAC, worked out with the formula above:
| Unit type | Device instance | For |
|---|---|---|
| Indoor unit device | 21007 | BACnet network number 2, RS-485 port 1, Indoor unit address 7 |
| Outdoor unit device | 21103 | BACnet network number 2, RS-485 port 1, Outdoor unit address 3 |
Source
Formula and objects from GW-BAC Commercial Air Conditioners SDV5 (user manual) (manufacturer document ↗), re-typed in our points list. Object names are shown as printed.
Check it against the live device. The calculator applies the formula from the manufacturer’s documentation; the gateway in front of you may expose fewer objects or use other numbers after a firmware change. Easy BACnet scans a network for BACnet IP devices from an Android phone and reads every object on them — a quick way to confirm one unit before you map a whole building.
Questions
How do I work out a Sinclair instance number?
Indoor unit device instance = network number x 10000 + port x 1000 + indoor address; outdoor units add 100 to the address. Network 2, port 1, indoor unit 7 is 21007; outdoor unit 3 on the same port is 21103. Every indoor unit device has the same object instances.
Is the Sinclair GW-BAC the same as the Systemair gateway?
They use the same device instance formula. The Systemair SYS GW IMS BAC(A) list also covers outdoor units and HTHM modules; it has its own calculator.
Is this Sinclair calculator official?
No. It applies the formula printed in Sinclair's own documentation to the points list in our library. Confirm the numbers against a scan of the live device before you map or write anything.
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