Yokogawa EJX/EJA-E pressure transmitter

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
pres	400	F32BE	1
sp	402	F32BE	1
et	404	F32BE	1
pres_usl	412	F32BE	1	kPa
pres_lsl	414	F32BE	1	kPa
pres_urv	416	F32BE	1	kPa
pres_lrv	418	F32BE	1	kPa
sp_usl	420	F32BE	1	MPa
sp_lsl	422	F32BE	1	MPa
sp_urv	424	F32BE	1	MPa
sp_lrv	426	F32BE	1	MPa
et_usl	428	F32BE	1	°C
et_lsl	430	F32BE	1	°C
et_urv	432	F32BE	1	°C
et_lrv	434	F32BE	1	°C
pres_damp	440	F32BE	1	s
sp_damp	446	F32BE	1	s
et_damp	452	F32BE	1	s
cap_temp	1128	F32BE	1
amp_temp	1130	F32BE	1

link settings as documented (unverified): RTU; default 9600 8N1; unit ID 1; FC 01,02,03,04,05,08,16,43; Turnaround delay time is configurable from 10 to 200 ms.

⚠ Do not connect power wiring to the MODBUS(RS-485) terminals. It may damage EJX Multivariable Transmitter. — Starkest reads only; we never write a control register.

bench facts as documented (unverified)

terminals	SUPPLY +, SUPPLY -, MODBUS A, MODBUS B, Ground terminal
A/B polarity	MODBUS A, MODBUS B
termination	Line termination can be selected by the hardware switch (Bus End / Not Bus End).
isolation	The EJX Multivariable Transmitter power supply is not electrically isolated from the RS-485 bus.
shield/ground	Grounding is always required for the proper operation of transmitters.
response timeout	3000 ms
inter-frame delay	100 ms
broadcast	supported
protocol notes	Host timeout period is recommended to be set larger than 3 s when transmitted data size is big. Host communication period between receiving response and sending request is recommended to be set larger than 100 ms under multi-drop connection.
model register	1005
serial register	1123
firmware register	1003
FC 43 device ID	supported
power	between 9 and 30 V dc with less than 2% ripple, and sufficient current capacity.
certifications	ATEX
doc revision	IM 01C25R05-01EN 1st Edition

generated by gemini:gemini-3.5-flash · harvested from https://web-material3.yokogawa.com/IM01C25R05-01EN.pdf (Yokogawa); 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.

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.