Foxmere Technologies

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S7-300 / S7-400 PLC Level 1


Course Outline

Upon completion of the course the student should:

  • Be able to recognise S7 hardware and be able to replace modules when a fault occurs.
  • Be able to operate the S7 software to make it perform certain tasks.
  • Understand basic S7 instruction set and be able to make minor modifications to software.
  • Be able to backup and restore a PLC program when required.
  • Be able to perform basic system diagnostics when a problem occurs.

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Equipment per Delegate

  • Siemens S7-300 or S7-400 PLC.
  • PC or laptop.
  • Simulator.

Course Content

To fault find a system you need to know exactly how it works.

How exactly does a PLC work?

  • The LED on the output card means I am getting voltage out right?
  • What exactly happens in-between? Theres more than just a program in the CPU.
  • How exactly does it scan the program?
  • What is this Watchdog Timer? Is it that important?
  • Can I use the same output twice? That's bad programming isn't it?
  • A PLC is a logic controller, so use a logical approach to fault find it.
  • What are the 8 simple test points to check?
  • What is the difference between forcing and toggling?

How do I do the following?

  • How do I check power is on and the PLC is in the right mode (RUN or Program).
  • Check for a fault condition.
  • Establish a link to the PLC (accessible nodes).
  • If comms problem check PG/PC interface.
  • Create a blank project and take a backup.
  • Open project for PLC and go online.
  • Interrogate diagnostics buffer.
  • Identify hardware / software faults.
  • Change the battery.
  • Change modules if necessary (with and without spares).
  • Identify if it is a PLC or comms fault (Profibus or MPI).
  • Check all settings against a template, node address, etc.
  • Check hardware configuration.
  • Clear memory and download program.
  • Check software against latest copy (compare function).
  • Monitor program.
  • Searching for specific operands and instructions.
  • Changing timer, counter values online.
  • Making minor modifications online and offline.
  • Check or create a VAT table to establish parameter status.
  • Force a parameter if required.
  • Call up reference data to assist with software diagnostics.
  • Archive and retrieve project.
  • Display documentation (symbols, comments).
  • Reassign an IO address and change software addresses (Rewire function).
  • Basic analog input configuration.
  • Printing cross reference / program listings, etc.

Background information also covered.

Understanding the following

  • Number formats, bits, bytes, words, double words.
  • Binary, HEX, octal, floating point, integer.
  • Data types and parameter types, bool, etc.
  • Block types.
  • Variable types (local and global).
  • How to monitor various blocks.
  • Ladder, STL programs.
  • Basic Instructions, contacts, set, reset, etc.
  • Timers and counters.
  • Comparators, maths.
  • How to make minor modifications.
  • Altering values in a VAT table.
  • Back-tracking through a program to establish where power flow stops.
  • Overall reset procedure.
  • Fault finding tips.


Provisional bookings can be made via email, phone or letter. Confirmation in writing with a purchase order number is required four weeks prior to the course start date.

Dates may be offered to other customers after this date.

Joining instructions are sent out approximately two weeks prior to the course start date.

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Course Times

Typical course times are 09:00 to 16:30. Alternative arrangements can be made for customised and on-site courses.


A light lunch will be provided when training at our in-house facility.

Payment and Cancellations

Fees are based upon payment being made to confirm course booking. Should you be unable to meet these terms please advise us as we will be able to re-quote on your payment terms.

Prices are quoted exclusive of VAT. New Customers are required to pay pro forma.

Requests for cancellation must be made via email or letter. Cancellation charges may apply.

Course Specifics


Siemens S7-300 / S7-400


Simatic Manager


5 days

Max. Delegates



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