FDL interface

To use the FDL interface, the multi-master operation must be activated in the master.

To do this, click on "Bus-Parameter (DP)":

Activate the multi-master operation:

Now activate the FDL interface via ADS-Write:

Data: 0xFF, all data are received, as well as the global control telegram. With the specification of the own PB address only data of the own PB address are copied into the buffer.

FDL receive

With ADS-Read, FDL indications received from another master or locally generated FDL confirmations are retrieved according to the length. For each FDL request sent, an FDL confirmation is returned.

Here the buffer must be polled by ADS READ to read data, if the data length is 1 with the data content 0x00 there is no data in the buffer. The buffer is 0x4000 bytes large; if more data is received, it is lost.

Example to write data (here 8 bytes of data are sent from master 01 to master 02):

FDL_DataSend: ARRAY[0..15] OF BYTE := [16#01,16#00,16#82,16#81,16#0C,16#0A,16#21,16#20,16#01,16#02,16#03,16#04,16#05,16#06,16#07,16#08];

Send FDL data:

Note: The length of the ADS must always be even. If the PB telegram has an odd length, set the length of the ADS to +1 to obtain an even length.

Read FDL data:

The FDL data should be polled via ADS Read. If the data length is 1, no data has arrived. If the query is slower than the incoming data, there may be several FDL telegrams in the buffer, which must then be read out.

It is recommended that the read length is always longer than the actual FDL telegram in order to remove several FDL telegrams from the buffer. The actual data length is displayed in ADSREADEX via the COUNT_R variable.

FDL-Error-Codes (0x22xx)