CPU in STOP
A stopped CPU without an immediately visible cause.
FIRST-LINE FIELD DIAGNOSTICS
Before opening STEP 7, identify what you need to verify
Enter the symptoms, LEDs and conditions observed at the control panel. BOJ S7-PLC PRO organizes possible causes and helps you decide whether to investigate the CPU, network, modules, power, signals or logic.
The app does not connect directly to the PLC and does not replace STEP 7 or qualified technical judgment.
A method built in industrial plants, not only in a classroom. Real work for:
- YPF
- Ledesma
- Generación Mediterránea
- TGN
- CALSA
- GETSA
START WITHOUT COMPLICATIONS
Try the workflow and choose a license when you are ready.
- Free trial
- Free · 14 days
- Subscription
- 44 USD per month
- One-time payment
- From 53 USD
TWO STAGES, ONE DIAGNOSTIC PROCESS
Orient the first response. Go deeper only when the evidence requires it.
BOJ S7-PLC helps the field technician arrive at online diagnostics with a narrower and more useful search.
01
FIRST RESPONSE
Guidance with BOJ S7-PLC
Record symptoms, LEDs and field conditions from a phone, tablet or browser.
02
ONLINE EVIDENCE
Diagnostics with STEP 7
Review hardware, events, blocks or registers with a more focused hypothesis.
TECHNICAL DECISIONThe technician evaluates the evidence before intervening.
BOJ S7-PLC guides.STEP 7 provides online evidence.The technician verifies and decides.
FIELD DIAGNOSTICS
Problems it helps organize
Identify the fault category before changing hardware or intervening in the process.
Active SF or BF
System or communication alarms that require structured checks.
PROFIBUS faults
Lost communication, missing nodes or unstable behavior.
Modules and signals
Unresponsive modules, I/O faults or inconsistent field signals.
Intermittent faults
Problems that appear and disappear before the cause is confirmed.
Production pressure
A clearer first response when troubleshooting time is limited.
WORKFLOW
How it works
From a symptom to prioritized hypotheses and practical field checks.
Enter the symptom
Record what you observe on the PLC and in the field.
Review prioritized hypotheses
The app organizes possible causes according to the evidence.
Verify in the field
Follow practical checks to confirm or rule out each cause.
DIAGNOSTIC TOOLS
What BOJ S7-PLC PRO includes
A practical environment for reviewing and documenting first-line diagnostics.
LED and symptom diagnostics
Interpret common operating states and fault symptoms.
Prioritized technical hypotheses
Hypotheses prioritized according to the available evidence and its relative weight.
Step-by-step verification
Clear checks to perform safely in the field.
Focused on S7-300/400
Technical guidance for classic Siemens CPUs and modules.
Installable web interface
Browser access with installation on compatible devices.
Support for teams
A shared method that reduces improvisation during diagnostics.
REAL APP WORKFLOW
Three real views of the professional workflow
See how the tool receives the symptom, guides one concrete check and prepares the technical record.
Start from the observed symptom
Filter by CPU, networks, signals or actuators and begin with the actual field condition.
Available in 6 languages
SpanishEnglishPortugueseGermanFrenchItalian
Interface available in six languages. Specialized technical content and legal documents are currently provided in Spanish.
LICENSES AND OPTIONS
Choose your PRO license
Compare renewal, duration, devices and offline availability before choosing.
Professional and Business include the S7-300/400 diagnostics course.
Free trial
Free- Free access for 14 days
- Online use only
- Some features are limited
- A practical way to explore the workflow
Monthly subscription
44 USD- App only, no course
- 1 device
- Automatic renewal until cancelled
- Offline use for up to 2 days
- Full PRO diagnostics
One-time monthly license
53 USD- App only, no course
- 1 device
- No automatic renewal
- Offline use for up to 2 days
- Full PRO diagnostics
Professional
224 USD- Full PRO App
- Permanent access to the course
- Offline use for up to 2 days
- For recurring professional use
Business
494 USD- Full PRO App
- Permanent access to the course
- Offline use for up to 7 days
- For maintenance and automation teams
- Purchase processed by Hotmart
- Price and billing model shown before confirmation
- Activation uses the email address entered during purchase
Companies and training centers: tailored pricing
Special conditions for organizations, technical training programs and teams with multiple users.
Is it only a fault table?
The self-paced PDF course teaches the diagnostic method; BOJ S7-PLC helps apply it to a particular case. Unlike a fixed checklist, the app keeps the symptom context and organizes hypotheses according to the evidence you enter: LEDs, Diagnostic Buffer, network state, modules and signals. It helps you decide what to verify first and what to rule out, including safety criteria for each step.
A fixed checklist
- Fixed list of faults
- Does not follow your symptom
- Does not prioritize evidence
- Relies on memory
BOJ S7-PLC
- Keeps the case context
- Guides each phase from the symptom
- Prioritizes hypotheses by evidence
- Includes safety criteria at every step
Access and availability
Use the app from a modern browser or install it on a compatible device.
Web access
No mandatory software installation.
Installable
Direct access on compatible devices.
Offline by plan
Offline duration depends on the selected license.
Prioritize checks before intervening
BOJ S7-PLC PRO helps organize symptoms and evidence before hardware is changed or equipment is restarted without a clear reason.
- Reduce trial and error under pressure.
- Prioritize evidence before intervening.
- Prepare a more focused STEP 7 session.
Who it is for
For professionals and teams troubleshooting Siemens S7-300/400 systems.
Industrial maintenance technicians
Instrumentation and electrical professionals
Automation specialists and PLC programmers
Companies operating Siemens S7-300/400 systems
Technical training centers
It supports the technician; it does not replace qualified technical judgment.
Developed with plant experience
BOJ S7-PLC PRO was developed by Walter Adrián Boj, an industrial automation specialist with experience in Siemens PLC diagnostics, maintenance, programming and industrial networks.
View professional profile15+ years
Industrial automation and diagnostics experience.
Siemens PLC
Focused on real S7-300/400 plant faults.
Field method
A structured process designed to reduce guesswork.
What technicians say
Real experience in the field.
Antes me costaba ordenar el diagnóstico cuando una CPU quedaba en STOP o aparecía BF. Con el curso entendí cómo analizar la falla por etapas y la app me sirve como guía rápida en planta. Hoy tengo más seguridad para intervenir sin empezar cambiando componentes al azar.Original testimonial in Spanish
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Frequently asked questions
Does the app connect directly to the PLC?
No. It works with the CPU state, LEDs, symptoms, network conditions and field evidence entered by the user.
Does it replace STEP 7 or a qualified technician?
No. BOJ S7-PLC organizes the first diagnostic response. STEP 7 and qualified technical judgment remain essential when deeper online analysis is required.
Can I use it without installing software?
Yes. It runs in a modern web browser and can also be installed as a web app on compatible devices.
Which plans include the course?
The Course + 1-month PRO App bundle, Professional and Business include permanent access to the S7-300/400 diagnostics course. The Monthly subscription and One-time monthly license include the PRO App only.
How does offline access work?
Offline availability depends on the selected plan: up to 2 days for monthly and Professional licenses, and up to 7 days for Business.
Is there an option for institutions?
Yes. Companies, institutions and training centers can request tailored conditions for multiple users or training programs.