verified connector library

Sierra QuadraTherm 640i/780i flow meter

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
actual_flow0F32LE1
actual_temp2F32LE1
actual_pressure4F32LE1
actual_total6F32LE1
alarm_status8U161
gas_index17U161
flow_unit_index22U161
user_full_scale23F32LE1
totalizer_unit_index27U161
temperature_unit_index29U161
pressure_unit_index34U161
standard_temperature35F32LE1
standard_temperature_index37U161
standard_pressure38F32LE1
standard_pressure_index40U161
normal_temperature41F32LE1
normal_temperature_index43U161
normal_pressure44F32LE1
normal_pressure_index46U161
alarm_active61U161
alarm_mode62U161
low_alarm_flow_trig63F32LE1
high_alarm_flow_trig65F32LE1
low_alarm_temp_trig67F32LE1
high_alarm_temp_trig69F32LE1
low_alarm_pressure_trig71F32LE1
high_alarm_pressure_trig73F32LE1
low_alarm_total_trig75F32LE1
high_alarm_total_trig77F32LE1
pipe_diameter79F32LE1
pipe_roughness81U161
pipe_diameter_units_index82U161
flow_correction83F32LE1
totalizer_enable85U161
totalizer_units_per_pulse86F32LE1
totalizer_pulse_width88U161
totalizer_reset89U161

link settings as documented (unverified): RTU; default 19200 8E1; unit ID 1; FC 03,04,06,08; Delay between receiving and transmitting = 8 ms

⚠ Before making adjustments to the device, verify the flow meter is not actively monitoring or reporting to any master control system. Adjustments to the electronics will cause direct changes to flow control settings. — Starkest reads only; we never write a control register.

bench facts as documented (unverified)
terminalsA terminal 13, B terminal 14, terminal 15 (Com)
A/B polarityA (-), B (+)
termination120 Ohm resistors at both ends of the cable
connectorTerminal board inside the QuadraTherm enclosure
isolationOptical isolated RS-485 interface, 1,500 Volts of isolation
shield/groundConnect the RS-485 common (shield wire) to terminal 15 (Com). It's better if it is not connected to Earth ground.
wiring notesUse a 24 AWG shielded twisted pair cable, with low capacitance, 120 Ohm impedance like Belden 9841.
inter-frame delay8 ms
protocol notesThe bootloader will only be active during the first two seconds after a power-up of the flow meter.
serial register40116
firmware register40120
identification notesPCA version at 40129
powerVoltage: 24 VDC +/- 10%, Amperage: 1.1 A or optional AC Voltage: 100 to 240 VAC, Amperage: 0.4 Amps RMS at 230 VAC
certificationsCE directives
doc revisionIM640i/780iV2-Modbus Rev. V2.A
firmware applicabilityv7.1

generated by gemini:gemini-3.5-flash · harvested from https://www.sierrainstruments.com/userfiles/file/manuals/640i-780i-modbus-instruction-manual.pdf (Sierra Instruments); 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.