STEP 7-Micro/WIN: from installation to a running program
Install Micro/WIN, connect the USB/PPI cable, set the PG/PC interface, find the CPU, then create a project, fill the symbol table, write, compile, download, run, monitor, force and export. Everything TP 0 asks for, step by step.
35 min
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STEP 7-Micro/WIN (V4.0) is the programming software of the S7-200. It is what runs on the lab PC next to the PLC-200. This lesson follows the order you use it in TP 0; the tour below shows where each step happens in the window.
Navigation bar
One click opens each part of the project: Program Block, Symbol Table, Status Chart, Data Block (initial V values), System Block (CPU settings, retentive ranges, passwords), Cross Reference, Communications, Set PG/PC Interface.
1. Installation
- Use STEP 7-Micro/WIN V4.0 with its last service pack (SP9). Run the setup as administrator, choose the language, and let it install the PG/PC interface when asked. Restart the PC if the setup requests it.
- SP9 is the version made for Windows 7 (32 and 64 bit). On newer Windows versions it generally installs, but it is not officially supported; the lab PCs are prepared by the instructor.
- Language and mnemonics: Tools → Options → General. Keep the SIMATIC mnemonic set (LD, A, O, =), which the booklet and this site use; the International set uses different, IEC-style mnemonics.
2. Connect and communicate
- Plug the USB/PPI multi-master cable into the PC and into port 0 of the CPU. The first time, Windows installs the cable driver.
- Set PG/PC Interface (navigation bar, or Windows control panel): choose PC/PPI cable (PPI) → Properties. On Local Connection choose USB (or the COM port if the cable is RS-232/PPI). On PPI, the PC address is 0 and the transmission rate 9.6 kbps.
- Open Communications and double-click Double-Click to Refresh. The CPU appears with its address (2 by default) and type. That is the first checkpoint of TP 0.
| Symptom | Likely cause |
|---|---|
| "No communication" / nothing found | wrong interface (not PC/PPI), USB driver missing, cable in port 1, trainer OFF |
| CPU found, but download refused | CPU in RUN with the mode switch on RUN: switch to STOP from Micro/WIN or on the CPU |
| Found at another address | the System Block of an earlier project changed port 0's address: select the address shown |
| Works then drops | USB hub or long cable: plug directly into the PC |
3. The project
A project (.mwp) holds everything: the Program Block (MAIN = OB1, subroutines SBR_n, interrupts INT_n), the Symbol Table, the Status Chart, the Data Block (initial values of V memory), the System Block (CPU settings: retentive ranges, input filters, passwords, output states in STOP), and the Cross Reference, the list of every address and where it is used.
PLC → Type: select CPU 224 and click Read PLC so that Micro/WIN checks the addresses against the real CPU.
4. Symbol table first
The booklet asks for every input, output, memory bit, timer and counter to be named in the symbol table before the first network:
| Symbol | Address | Comment |
|---|---|---|
| START | I0.0 | start push button, momentary |
| STOP_NC | I0.1 | stop, normally closed: ON = healthy |
| RUN | Q0.0 | motor contactor |
View → Symbolic Addressing then shows START instead of I0.0 in the program. Every editor on this site has the same symbol table and exports it as Micro/WIN's tab-separated copy.
5. Write, compile, download, run
- Drag contacts and coils from the instruction tree into Network 1; type a symbol or address above each one; give each network a title and a comment.
- PLC → Compile All (✓): the output window must say 0 errors.
- CPU to STOP, then File → Download (⤓): tick the program block, data block and system block.
- Check the enable switches of the TP, then RUN (▶). The green RUN LED lights.
6. Monitor, then force (carefully)
- Debug → Program Status: energised contacts and coils are shown live (blue in Micro/WIN, green on this site), timers show their current values. In STL view the columns show the logic stack.
- Status Chart: type addresses and switch Chart Status on. You can write a value into V or M, or force an I or Q.
- A forced value wins over the program and over the real switch, until you unforce it. TP 0 asks you to force I0.0 and explain why forcing must be removed before a machine is handed over: a forced output ignores every stop in the program.
Practise the whole sequence on the virtual trainer: the STL below is TP 0's kind of network. Switch the CPU to STOP and back to RUN while the output is ON, and note what happens to Q0.0 (TP 0, question 3).
No errors: the program compiles.
7. Save, export, print
- File → Save keeps the
.mwpproject. - File → Export writes the program as an
.awltext file (statement list with network titles and comments). File → Import reads one back. The STL runner above opens.awlfiles: test your exported program at home before the session. - File → Print prints networks, symbol table and cross reference for the report.