3/9/2009 9:31 AM | |
Posts: 2930 Rating: (432)
|
Hi, this is no problem. Use the XMT instruction to send data from the PLC. To get it to RS232 use the RS232 PC-PPI cable. There are several free examples available from Siemens. 1. Tips&Tricks. This you can find on the second CD-ROM of MicroWIN or in the support pages in Internet from Siemens 2. Check www.siemens.de/microset Basically with the XMT instriction you can send max. 255 ASCII charackters Bytes). You can now decide if you want to use one byte for each digital signal or you write each dig signal in one bit (232 bits = 29Bytes and seperate it later. Here an example whare you can tranfer 4Bytes Inpout and 4 Bytes Outputs via Freeport: I hope this helps Helmut AttachmentDigital values via freeport.zip (155 Downloads) |
3/10/2009 2:41 PM | |
Joined: 10/30/2008 Last visit: 9/13/2024 Posts: 64 Rating: (2) |
Hi aante! Usually in serial protocols the master send a "bus package" and the slave returns other "bus package" including the CRC answer. Using the outputs you have to write the protocol (this isn´t complicate, but is arduous to make). I suggest you to use two inputs for read the slaves' answers. Attention for the output and input speed and never send a data during a receive.. I don´t know with witch protocol you are working, if is modbus click in the linksto help youfor write thecommunication. http://www.modbustools.com/PI_MBUS_300.pdf Phisically, you need to use optocouplers or similar depending the voltage of the bus, again attention for the speed of the component Suggestion: Try to find a parcial or complete program with this aplication |
Tiago Martins Machado |
|