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BACnet instance calculator · Setra Power Meter (SPM) load device
Setra SPM BACnet Instance Calculator (CT 1-3)
Free browser tool · nothing is uploaded · 5 November 2026
Each Setra SPM load device prints only the CT 1 block and reserves the same block for CT 2 and CT 3, 30 instances further on.
CT n's objects are the CT 1 instance + 30 x (n - 1): CT 1 is AI 30-52, CT 2 AI 60-82, CT 3 AI 90-112. CT 2's real power is AI 62; its polarity correction is BV 2.
Setra calculator
The calculator needs JavaScript. The formula and a worked example are below.
Which unit does this instance belong to?
How the numbers are built
instance = CT 1 instance + 30 x (CT - 1); polarity = BV CT
| Part | Meaning | Range |
|---|---|---|
| CT | Current transformer number on the load | 1-3 |
| CT 1 instance | Printed CT 1 instance | 30-52 |
Load-level totals (voltage, power, energy) are fixed objects on each load device.
Worked example: CT 2
The first objects for CT 2 on the SPM load device, worked out with the formula above:
| Object | Name (as printed) | What it is |
|---|---|---|
| AI 60 | CT# 1 Amperage (A) | First CT block (AI 30-52) |
| AI 61 | CT# 1 Demand | |
| AI 62 | CT# 1 Real Power (kW) | |
| AI 63 | CT# 1 Apparent Power (kVA) | |
| AI 64 | CT# 1 Reactive Power (kvar) | |
| AI 65 | CT# 1 Harmonic Distortion (HD) | |
| BV 2 | CT# 1 Polarity Correction | Polarity correction for CT 1 (BV 2, BV 3 for CT 2, 3) |
Source
Formula and objects from Setra Power Meter Master BACnet Object List · SS-SPM-BAC-OBJ · rev. Rev H (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 Setra instance number?
CT n's objects are the CT 1 instance + 30 x (n - 1): CT 1 is AI 30-52, CT 2 AI 60-82, CT 3 AI 90-112. CT 2's real power is AI 62; its polarity correction is BV 2.
Why does the meter show more than one BACnet device?
The SPM is a root device for the voltage inputs plus one load device per configured load. The CT blocks are inside each load device.
Is this Setra calculator official?
No. It applies the formula printed in Setra'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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