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S7-200 Tip : Changing Direction

Special Hardware Requirements: None

This programming example shows how to control a three-phase induction motor with two possible rotational directions.
Use the momentary contact switch at input I0.0 to start the motor counterclockwise. Use the momentary contact switch at input I0.1 to start the motor clockwise. The prerequisites are that the motor circuit breaker at input I0.3 and the OFF switch at input I0.2 are not activated. The rotational direction cannot be changed until after the OFF switch is pressed and a waiting period of 5 s has elapsed. This allows the motor to brake and start up in the opposite direction.

S7-200 Tip : Networking with GSM Modem

Special Hardware Requirements:
For each station            1 x PC/PPI cable
For each station            1 x ELSA Micro Link 56k FUN modem or
                                    Siemens TC35 GSM modem
For each station            1 x Gender changer (male)

Functions:

1.                  Analog Modem
a.     Send data from an S7-200 head station to an S7-200 substation
b.     Send data from an S7-200 substation to an S7-200 head station

2.                  GSM Modem
a.     Send data from S7-200 head station to S7-200 substation
b.     Send data from an S7-200 substation
c.      Send messages from S7-200 substation
          -   SMS
            -   E-mail
            -   Fax

1.1 Overview

S7-200 Tip : S7-200 PPI Network Notes

Special Hardware Requirements: None

Overview

Token Ring Networks

Gap Updates

Tokens, Masters, and Slaves

Bringing in a New Master

“Busy’s” and Starving

CP vs PC/PPI

Busy’s Revisited

Addendum A: A Note for Micro/WIN and Micro/DOS Users

Addendum B: Network Component Matrix

Addendum C: Physical Data

Addendum D: Panel-Tec Information

General Notes

Networking
The four connected devices in Figure 42.1 form a simple network. There are two CPU 224s and two CPU 222s. This network will be the basis for a discussion of more complicated networks and will help to illustrate some of the Dos and Don’ts of networking. We will be using PPI protocol for our communication. PPI is the default communications protocol of the CPU 224 and CPU 222. Freeport mode (in which serial communications are handled by the user program) are not discussed here.

S7-200 Tip : Modbus RTU Slave

Special Hardware Requirements: None

Note! Starting with STEP 7-Micro/WIN Version 3.2, a MODBUS Protocol Library (Optional Add-On Instruction Library 6ES7 830-2BC00-0YX0) was added.
As a result, the new library now provides an easier method of programming this task than is shown here

This program example includes a group of subroutines and interrupt routines which create a Modbus RTU slave using the Freeport functions of the S7-200. Modbus RTU is a binary protocol.

S7-200 Tip : Using XMT/RCV

Special Hardware Requirements:
Operator Interface
This program uses the Terminal program that is shipped with Windows 3.1 (called HyperTerminal in later versions of Windows). The Terminal program should be configured as follows: