Real-time Monitoring
Auto-refresh from 0.5 to 10 seconds, without requests piling up. You can watch a controller while it works.
PLC-Inspector · Modbus/TCP for Siemens LOGO! 
Professional PLC Memory Viewer
Monitor and analyse your Siemens LOGO! PLC memory in real time via Modbus/TCP. Available for Mac, iPhone, iPad and Android.
Reading is free · writing unlocked once · no subscription
Write access
Set a value, see the effect at once
Write a holding register straight from the memory view and watch in the same window how the controller reacts. Changes are highlighted while they happen.
Because writing moves real machinery, it takes two steps on purpose: switch on write mode, check the value, confirm. If you are commissioning for hours, turn the prompt off for the session. It is back the next time you open the view.
Pro Writing is the Pro function. Reading, watching and analysing stay free.
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Switch on write mode
It has to be enabled deliberately and lapses on its own when you leave the view.
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Enter the value
Decimal or hexadecimal. The preview shows both notations and the bit pattern.
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Confirm
The app checks what the PLC mirrors back and reports separately if the confirmation does not match the order.
Features
Powerful Features
Everything you need to monitor and debug your Siemens LOGO! PLC controllers.
Change Detection
Changed registers are highlighted in orange, counted, and you can jump between them with the arrow keys.
Multi-Station Support
Manage multiple PLC stations with custom names and easily switch between them.
LOGO! 8 Support
Full support for Siemens LOGO! 8 (0BA8) over Modbus/TCP. Earlier LOGO! generations have no Modbus interface.
Binary Display
View register values in hexadecimal, decimal and binary format simultaneously for detailed analysis.
Universal App
Buy once, use everywhere: Mac, iPhone and iPad. Available in ten languages.
Universal App
One App, All Your Devices
The Mac at the desk, the iPhone at the cabinet. And on Android the same app, phone or tablet.
Available on macOS, iPadOS, iOS and Android
Technology
Proven Technology
PLC-Inspector uses binary communication routines for the Modbus/TCP protocol developed by spiritdev. These routines have proven themselves in various industrial applications and guarantee reliable, fast communication with your PLC.
Learn more about spiritdev Reliability
Trustworthy when it counts
A diagnostic tool is only worth something if you can rely on what it shows.
Complete responses, even for large reads
Up to 125 registers in one go are reassembled correctly, even when the answer arrives split across several TCP packets.
Every answer is matched to its request
A late response to an earlier request can never appear as a current value. In a diagnostic tool that is the worst possible error.
Errors in plain language
Modbus exceptions and connection problems are explained in words instead of an error number.
One connection per station, strictly serialised
A LOGO! tolerates only a single TCP connection. The app respects that and queues its requests.
In Action
Screenshots
See PLC-Inspector in action.
Free and Pro
Read for free, write once bought
The app is free. Only writing registers is behind a one-time purchase, because that is the part that moves real machinery.
Free
Reading is free and stays free.
- VM memory, analogue inputs and outputs in real time
- Bit view, change detection and auto refresh
- As many controllers as you need, export included
Pro
One-time purchaseWriting registers is unlocked once.
- Write holding registers, decimal or hexadecimal
- Echo check and confirmation before every write
- Every future Pro function included
No subscription and no account. On Apple one purchase covers Mac, iPhone and iPad. Your store shows the current price.
Download
Download Now
For Mac, iPhone and iPad in the App Store. For phone and tablet on Google Play.
Support
Support
Need help? Have questions or suggestions? We are here to help.