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BACnet instance calculator · SYS GW IMS BAC(A) VRF gateway
Systemair SYS GW IMS BAC BACnet Device ID Calculator
Free browser tool · nothing is uploaded · 5 November 2026
The Systemair SYS GW IMS BAC(A) (IMMP-BAC in the manual) makes every SYSVRF indoor and outdoor unit its own BACnet device, numbered from the network number, port and unit address.
Indoor unit device instance = network number x 10000 + port x 1000 + indoor address; outdoor units add 100 to the address. Network 5, port 2, indoor unit 14 is 52014; outdoor unit 0 on that port is 52100.
Systemair 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 on the gateway's web page (each gateway needs a different one) and restart it. Port 0 is the RS-485 port next to the Ethernet port.
Worked example: network 5, port 2, indoor unit 14
The first objects for network 5, port 2, indoor unit 14 on the SYS GW IMS BAC(A), worked out with the formula above:
| Unit type | Device instance | For |
|---|---|---|
| Indoor unit device | 52014 | BACnet network number 5, RS-485 port 2, Indoor unit address 14 |
| Outdoor unit device | 52100 | BACnet network number 5, RS-485 port 2, Outdoor unit address 0 |
| HTHM (high-temperature hydro module) device | — |
Source
Formula and objects from Operation and Installation Manual - IMMP-BAC(A) 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 Systemair instance number?
Indoor unit device instance = network number x 10000 + port x 1000 + indoor address; outdoor units add 100 to the address. Network 5, port 2, indoor unit 14 is 52014; outdoor unit 0 on that port is 52100.
What do the Systemair error code numbers mean?
0 is no error; then blocks of 20 per letter (1-20 = A0-AU, 21-40 = b, 41-60 = C and so on). The unit's service manual gives the meaning of each code.
Is this Systemair calculator official?
No. It applies the formula printed in Systemair'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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