PLC IO Check & Monitor MELSEC

PLC IO Check lets you quickly check and monitor the I/O status of
Mitsubishi MELSEC PLCs in the field. Connect to the PLC directly over
Ethernet from your phone — no PC or special hardware required — and read
device values in real time.

■ Features
• IO Check — verify your registered X/Y I/O in the field as OK/NG (Manual, Auto, and Guided-sequence modes). Automatically flags cross-wiring and shorts, shows OK/NG badges in the list, and shares a CSV/summary report
• Direct MC Protocol / SLMP communication over Ethernet (TCP/UDP), 3E/4E Frame, Binary/ASCII
• ON/OFF monitoring of bit devices (X/Y/M/L/B)
• Word device values (D/W/ZR) — decimal/hex, signed/32-bit/float/string display
• Unlimited device registration, auto-polling and manual refresh (no limit on simultaneous live monitoring)
• Auto-registration — create device sequences from a start address, step, and count
• Organize devices into collapsible hierarchical groups with drag-to-reorder, delete a whole group, and expand/collapse all groups at once
• Group/search/status filters, isolated error display
• Batch Monitor — enter devices and addresses directly to read multiple values at once in a table
• IO Grouping — visualize device I/O at a glance with cards that separate input and output signals
• Save, load, and share multiple projects (.plc files, portable across devices)
• App display language — Korean / English / Japanese, dark/light theme
• GX Works import — open a GX Works2 project (.gxw) file directly, or bulk-register from comment/ladder CSV (comment recovery including inputs/outputs (X/Y), auto-group by device type or by POU (which program controls each device), POU tree preview, double-coil warnings, import preview filter by device type, per-code selection, comment merge)
• In-app GX Works setup guide — PLC parameter setup steps from the connection screen help
• Calculator & Tools — built-in Programmer (radix/bitwise), Electronic gear ratio (MR-J servo CMX/CDV), Circle, and Trigonometry (right-triangle side↔angle, coordinates→bearing/distance) calculators, plus an ASCII code table and an ASCII Converter (char↔code, PLC D-register word values)

※ All features are free — no tokens, in-app purchases, or feature locks. Everything, including Batch Monitor, IO Grouping, and the calculator tools, is available alongside a bottom banner ad.

■ Supported
• MELSEC Q series (verified with QJ71E71-100 module and QnUDV built-in Ethernet)
• MELSEC iQ-R series (verified with RJ71EN71 module and built-in Ethernet)
• MC Protocol (SLMP) compatible Ethernet configurations

■ Safety
• This app is read-only (monitoring). It does not modify equipment.

This is a third-party utility for fast field I/O checks.

Disclaimer: This app is an independent third-party application and is NOT
affiliated with, endorsed by, or approved by Mitsubishi Electric Corporation.
"MELSEC", "GX Works" and related names are trademarks of their respective
owners and are used here solely to indicate compatibility.

GX Works2 (.gxw) import is a compatibility convenience that extracts devices
and comments from files you own. Results are for reference only — some devices
or comments may be missing or interpreted differently, so always verify before
field use. For complete, accurate data, exporting a comment CSV from GX Works2
is recommended. Password-protected (secured) files are not opened.