Grundfos CUE drive
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 |
|---|
| parameter_index | 8 | U16 | 1 | |
| configuration_mode_1_00 | 999 | U16 | 1 | |
| motor_current_1_24 | 1239 | U32BE | 0.01 | A |
| control_word_2810 | 2809 | U16 | 1 | |
| bus_reference_2811 | 2810 | I16 | 1 | % |
| status_word_2910 | 2909 | U16 | 1 | |
| main_actual_value_2911 | 2910 | I16 | 1 | % |
| maximum_reference_3_03 | 3029 | U32BE | 0.001 | RPM |
| status_word_16_03 | 16029 | U16 | 1 | |
| main_actual_value_16_05 | 16049 | I16 | 1 | % |
| motor_current_16_14 | 16139 | U32BE | 0.01 | A |
| digital_inputs_16_60 | 16599 | U16 | 1 | |
| control_word_50000 | 49999 | U16 | 1 | |
| bus_reference_50010 | 50009 | I16 | 1 | % |
| status_word_50200 | 50199 | U16 | 1 | |
| main_actual_value_50210 | 50209 | I16 | 1 | % |
link settings as documented (unverified): RTU; baud 2400/4800/9600/19200; FC 01,03,05,06,08,11,15,16,17; If the baud rate is greater than 19200, then the 3.5 character time is replaced by a timeout time of 1.75 ms.
⚠ Grundfos recommends only using one of the three mentioned ways to control the frequency converter! Grundfos recommends register 2810-2873 and 2910-2973 to control the frequency converter ensuring compatibility with all controllers. Par. 200-52 Control Source Request is to be set to 1 Remote to control the CUE via Modbus. — Starkest reads only; we never write a control register.
bench facts as documented (unverified)
| broadcast | supported |
| protocol notes | Modbus RTU messages addressed to zero are broadcast messages. No response is permitted for broadcast messages. |
| doc revision | 93525145 11.2025 |
field reports — community-sourced, unverified (checked 2026-06-11)
- confirmed: baud_rates: [2400, 4800, 9600, 19200] — confirmed by Native Modbus RTU for CUE - Grundfos manual (parameter 8-32)
- confirmed: framing: ['RTU'] — confirmed by Native Modbus RTU for CUE - Grundfos manual (parameter 8-30)
- confirmed: function_codes: [1, 3, 5, 6, 8, 11, 15, 16, 17] — confirmed by Native Modbus RTU for CUE - Grundfos manual (section 3.10)
- confirmed: parity: 'E', stop_bits: 1 — confirmed by Native Modbus RTU for CUE - Grundfos manual (parameter 8-33 default)
- confirmed: timeout note: 'If the baud rate is greater than 19200, then the 3.5 character time is replaced by a timeout time of 1.75 ms.' — confirmed by Native Modbus RTU for CUE - Grundfos manual (section 3.2)
- confirmed: control_warning: 'Grundfos recommends only using one of the three mentioned ways to control the frequency converter! Grundfos recommends register 2810-2873 and 2910-2973 to control the frequency converter ensuring compatibility with all controllers. Par. 200-52 Control Source Request is to be set to 1 Remote to control the CUE via Modbus.' — confirmed by Native Modbus RTU for CUE - Grundfos manual (section 4.1)
- confirmed: doc_revision: '93525145 11.2025' — confirmed by Native Modbus RTU for CUE - Grundfos manual footer
- confirmed: broadcast_supported: true, notes: 'Modbus RTU messages addressed to zero are broadcast messages. No response is permitted for broadcast messages.' — confirmed by Native Modbus RTU for CUE - Grundfos manual (section 3.5)
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.