Daniel Trautmann
IBHsoftec GmbH
Profibus Master Stack - FDL Status Request
Hi,
with the CIF50-PB it was possible to send an "FDL_Status_Reply" request (command 0x9b) to another master. Now I want to do the same with a cifX50 Profibus master card, but I can not figure out which message I have to send to the DL stack.
Could someone give me a hint?
Thanks in advance
Daniel
Daniel Trautmann
IBHsoftec GmbH
Hi,
I need to check if the other station is on the bus every 100ms when there are no other telegrams exchanged between the stations. Is the PROFIBUS_FSPMM2_CMD_LIVE_LIST_REQ Request fast enough to to this or will this be too much load on the bus?
Hi dj999,
the time for collecting the life list data depends on the configured HSA, the baudrate and the Profibus timings. Also the number of the remote stations and there type (master or slave) matters.
A short test with 187,5 kBit, MPI-Timings, HSA=32 and one other master results in a reaction time smaller 14 ms.
Another test with 12 MBit and same conditions results in a reaction time smaller 6 ms.
Daniel Trautmann
IBHsoftec GmbH
Hi Johnny,
I just tested the LiveList command, but on the Profibus here in our Office (1,5 MBit, HSA=127, 5 slaves, 8 other masters, about 400 bytes of i/o data and some FDL communication), I get a response time of 375 ms, sometimes it is even greater than 1 s.
Ok, 1 second is more as I expected. The master which generates the list has to wait until it gets the Profibus token, send one FDL-Status to address 0, wait for answer or timeout and send the next FDL-Status to address 1 and so on (or give to token to the next master). Depending on the bus load (and the current owner of the token) this takes time.
The good news for you: if your master is removed from the bus (and your 100 ms timeout occurs) the LiveList-Generation should be as fast as I wrote.
Andreas Jacob
Hilscher Gesellschaft fuer Systemautomation mbH
Hi dj999,
a comparable command to send a FDL_Status_Request to a device, does not exist in the netX based PROFIBUS master FW.
As far as I know did Hilscher collect this issue to the feature request list. This means, that this will be available in one of the future versions of the stack, but without any information about the time line.
But you can use the command PROFIBUS_FSPMM2_CMD_LIVE_LIST_REQ 0x00004430 as an alternative. This command sends also the FDL_Status request on the bus. But it will send a FDL_Status_Request to all addresses on the bus (till to the configured HSA "Highest Station Address"). Please keep in your mind that this workaround will generate more traffic on the bus. A slave address which is higher then the HSA will not be requested.