WEG CFW500 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 only confirmed at the hardware-verified rung.
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 |
|---|
| serial_interf_status | 316 | U16 | 1 | |
| logical_status | 680 | U16 | 1 | |
| speed_in_13_bits | 681 | I16 | 1 | |
| serial_usb_control | 682 | U16 | 1 | |
| serial_usb_speed_ref | 683 | I16 | 1 | |
| dox_value | 695 | U16 | 1 | |
| aox_value_1 | 696 | I16 | 1 | % |
| aox_value_2 | 697 | I16 | 1 | % |
| aox_value_3 | 698 | I16 | 1 | % |
link settings as documented (unverified): RTU; default 19200 8E1; unit ID 1; FC 01,02,03,04,05,06,15,16,43
bench facts as documented (unverified)
| terminals | Pin 14: RS485-A(-), Pin 16: RS485-B(+), Pin 18: GND |
| A/B polarity | Pin 14 is A(-), Pin 16 is B(+) |
| termination | 120 Ohm | 0.25 W resistor connected between +B and -A |
| connector | Control terminal (CFW500-IOS), mini-USB (CFW500-CUSB), DB9 (CFW500-CRS232) |
| isolation | Galvanically insulated |
| shield/ground | Shielded cable with twisted pair, shield must be grounded |
| broadcast | supported |
| FC 43 device ID | supported |
| doc revision | 04 |
field reports — community-sourced, unverified (checked 2026-06-11)
- The Modbus RTU telegrams for request and response cannot exceed 64 bytes. Attempting to read large blocks of registers (e.g., up to 125 registers) will fail due to this buffer limit. [source]
- In firmware versions prior to V4.1X, attempting to read a range of registers that includes a missing or skipped parameter (e.g., reading from P0007 to P0009 where P0008 is skipped) causes the drive to return an error or nothing for all parameters in that range. Firmware V4.1X resolved this by adding support for Modbus read/write continuity even with invalid addresses in the sequence. [source]
- confirmed: comms defaults (baud rates [9600, 19200, 38400], default baud 19200, default unit ID 1, RTU framing, parity E, stop bits 1) — confirmed by WEG CFW500 Modbus RTU User's Guide (Doc 10002253377, Rev 04) parameters P0308, P0310, and P0311
- confirmed: supported Modbus function codes (1, 2, 3, 4, 5, 6, 15, 16, 43) — confirmed by Table 5.1 of the Modbus RTU CFW500 User's Guide
- confirmed: physical connector options (Control terminal CFW500-IOS, mini-USB CFW500-CUSB, DB9 CFW500-CRS232) — confirmed by Section 2 of the Modbus RTU CFW500 User's Guide
- confirmed: RS485 terminals and polarity (Pin 14 is A(-), Pin 16 is B(+), Pin 18 is GND) — confirmed by Table 2.1 of the Modbus RTU CFW500 User's Guide
- confirmed: termination resistor (120 Ohm | 0.25 W connected between +B and -A) — confirmed by Section 3.3 of the Modbus RTU CFW500 User's Guide
- confirmed: broadcast supported on address 0 — confirmed by Section 1.1 of the Modbus RTU CFW500 User's Guide
- confirmed: register map summary (serial_interf_status @ 316, logical_status @ 680, speed_in_13_bits @ 681, serial_usb_control @ 682, serial_usb_speed_ref @ 683, dox_value @ 695, aox_value_1 @ 696, aox_value_2 @ 697, aox_value_3 @ 698) — confirmed by the parameter list and Modbus RTU memory map where parameter numbers map directly to 0-based Modbus addresses
generated by gemini:gemini-3.5-flash · harvested from https://static.weg.net/medias/downloadcenter/h73/ha4/WEG-CFW500-modbus-rtu-manual-10002253377-en.pdf (WEG); manual-faithful — the document's claims, panel risk: ELEVATED — panel is not confident; proved interop-verified on 2026-06-10 · recorded 2026-06-10
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.