Liebert/Vertiv UPS (IntelliSlot Modbus)
Register map(s) for this device, each at the trust rung it earned. Addresses are 0-based
as on the wire. Word order and scaling are confirmed at the hardware-verified rung and at no rung below it.
interop-verified
Read + decoded cleanly over a real network vs an independent third-party Modbus test server (transport and framing; reads are remapped into the server's register window, so the map's own addresses are NOT exercised). Does NOT prove word order/scaling against the actual device.
| point | address (0-based) | type | scale | unit |
|---|
| voltage_in_x_y | 0 | U16 | 1 | |
| voltage_in_y_z | 1 | U16 | 1 | |
| voltage_in_z_x | 2 | U16 | 1 | |
| voltage_out_a_b | 3 | U16 | 1 | |
| voltage_out_b_c | 4 | U16 | 1 | |
| voltage_out_c_a | 5 | U16 | 1 | |
| voltage_out_a_n | 6 | U16 | 1 | |
| voltage_out_b_n | 7 | U16 | 1 | |
| voltage_out_c_n | 8 | U16 | 1 | |
| current_out_a | 9 | U16 | 1 | |
| current_out_b | 10 | U16 | 1 | |
| current_out_c | 11 | U16 | 1 | |
| ground_current | 12 | U16 | 0.1 | |
| neutral_current | 13 | U16 | 1 | |
| kva | 14 | U16 | 1 | |
| kw | 15 | U16 | 1 | |
| frequency | 16 | U16 | 0.1 | |
| percent_capacity_a | 17 | U16 | 1 | |
| percent_capacity_b | 18 | U16 | 1 | % |
| percent_capacity_c | 19 | U16 | 1 | deg C |
| power_factor | 20 | U16 | 0.01 | deg C |
link settings as documented (unverified): RTU; baud 9600/19200/38400; FC 01,02,03,04,05,06,15,16; Supports EIA-485/422 2 wire physical port.
bench facts as documented (unverified)
| terminals | 2 wire |
| connector | EIA-485/422 |
| wiring notes | Supports EIA-485/422 2 wire physical port. |
| max registers/read | 127 |
| protocol notes | Write Multiple Registers supports writing values into a block of contiguous registers (1 to 120). |
| doc revision | SL-28170_REV11_03-14 |
field reports — community-sourced, unverified (checked 2026-06-11)
- Users attempting to read registers on specific models (e.g., Liebert GXT5) may encounter IllegalAddress errors if they attempt to read holding registers (FC 03) instead of input registers (FC 04) as specified in the manual. [source]
- On some Liebert GXT MTX+ models, users report being unable to read discrete input status bits (starting at 10002 / 10042) using standard Modbus scanners, while holding registers are accessible. [source]
- Frequency and Power Factor registers require scaling (divided by 10 and 100 respectively) to obtain the actual values, which can cause integration confusion if not handled in the client. [source]
- confirmed: comms defaults (baud rates 9600/19200/38400, RTU framing, parity N, stop bits 1, EIA-485/422 2-wire physical port) — confirmed by Table 2.1 of SL-28170 [12.1.2]
- confirmed: function codes [1, 2, 3, 4, 5, 6, 15, 16] — confirmed by Table 2.2 of SL-28170
- confirmed: quirks (max_read_registers: 127, Write Multiple Registers supports writing values into a block of contiguous registers 1 to 120) — confirmed by Section 2.3 of SL-28170
- confirmed: register map summary (voltage_in_x_y @ 0, voltage_in_y_z @ 1, etc.) — confirmed by Table 3.42 (FPC, PPC—Input and Holding—PMP2) and Table 30 (Liebert PowerSure Interactive) of SL-28170
The trust ladder
Each rung states what it proved and what it did not. Gray until proven; green is earned by hardware only.
- generated — A prompt produced it. Unproven — anyone can regenerate this.
- structure-verified — Decode path is structurally sound (addresses, widths, finite values). Does NOT prove word order or scaling.
- interop-verified — Read + decoded cleanly over a real network vs an independent third-party Modbus test server (transport and framing; reads are remapped into the server's register window, so the map's own addresses are NOT exercised). Does NOT prove word order/scaling against the actual device.
- simulator-verified — Decoded correctly against a protocol emulator seeded with known-true values — catches word-order/scaling errors vs the emulator, not the physical device.
- hardware-verified x1 — Matched a real device with operator-attested readings as ground truth — the only rung that confirms word order + scaling on the wire.