Serial interface module (ASCII 1SI) Siemens

Hi friends, does anyone know how to clear the buffer of this module?

I uses it to interface with a scanner via RS232, but sometimes the scanner scans some unexpected barcode, so I want to clear the buffer everytime starting up. (But dont know how to clear it )

Thanks all for your helps.

cmet,

Deleting the message buffer during start up is nice and simple...

In the hardware configuration, right click the 1SI and select properties, select the parameter tab, at the bottom of this list is a check box for 'delete recieve buffer during cpu startup'.

Is that what you were after?

Paul

Hi PLucas, thanks for your response. What I really want is to clear the buffer while the cpu is still running. Is this possible to do so?

cmet,

As far as I am aware, the message buffer is cleared after each activation of FB2 (P_RCV), the message buffer will contain more than one message if you have 'dynamic message frame buffer' option set in the configuration then the 'oldest' message will be cleared.

You could set the configuration up so that you don't allow 'dynamic message frame buffering' and you don't allow 'message frame buffer overwriting', this will then ensure that the buffer contains only one message at a time and this will be cleared everytime FB2 is set. The downside of this is that if the messages are coming in thick and fast (from your barcode reader) you could 'miss' one.

Paul