verified connector library

Mitsubishi QJ71MB91 Modbus module

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.

pointaddress (0-based)typescaleunit
ch1_error_response_code2U161
ch2_error_response_code4U161
ch1_detailed_led_status6U161
ch2_detailed_led_status7U161
ch1_bus_message_count3840U161
ch1_bus_communication_error_count3841U161
ch1_character_overrun_error_count3842U161
ch1_message_discard_count3843U161
ch1_data_discard_count3844U161
ch1_failed_transmission_count3845U161
ch1_slave_message_count3846U161
ch1_slave_no_response_count3847U161
ch1_slave_nak_count3848U161
ch1_slave_busy_count3849U161
ch1_exception_error_count3850U161
ch1_communications_event_count3851U161
ch2_bus_message_count3904U161
ch2_bus_communication_error_count3905U161
ch2_character_overrun_error_count3906U161
ch2_message_discard_count3907U161
ch2_data_discard_count3908U161
ch2_failed_transmission_count3909U161
ch2_slave_message_count3910U161
ch2_slave_no_response_count3911U161
ch2_slave_nak_count3912U161
ch2_slave_busy_count3913U161
ch2_exception_error_count3914U161
ch2_communications_event_count3915U161

link settings as documented (unverified): RTU/ASCII; default 19200 8E1; FC 01,02,03,04,05,06,07,08,11,12,15,16,17,20,21,22,23; Supports both master and slave functions. Link operation function allows CH1 (RS-232) to communicate with multiple slaves on CH2 (RS-422/485).

bench facts as documented (unverified)
terminalsCH1: D-Sub 9-pin female, CH2: Detachable terminal block (M3 screws)
A/B polaritySDA/SDB for transmission, RDA/RDB for reception
terminationRS-422: 330 ohm 1/4 W, RS-485: 110 ohm 1/2 W
shield/groundGround the shield at one end
wiring notesRS-232 cable connector screw is M2.6
max registers/read125
response timeout30000 ms
broadcastsupported
protocol notesResponse monitoring timer default is 30 seconds (30000 ms). Broadcast delay default is 400 ms.
identification notesFC17 (Report Slave ID) returns programmable controller CPU type data.
FC 43 device IDnot supported
power5VDC internal current consumption: 0.31A
environmentMeets the general specifications in the user's manual for the CPU module used.
doc revisionSH(NA)-080578ENG-K

generated by gemini:gemini-3.5-flash · harvested from https://dl.mitsubishielectric.com/dl/fa/document/manual/plc/sh080578eng/sh080578engk.pdf (Mitsubishi Electric); 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.

Have a device that isn't here? Upload its register map — generation is free, and the connector earns its rung by being proven, not claimed.

Need it proven on your own device? Hardware verification — if it doesn't verify, you don't pay.

Building a platform? License the verified library — machine-readable maps, firmware matrix, API access.