Need help on SFC51

Hello Gurus,

I am currently commissioning a PLC-SCADA project. The control system has Siemens Redundant S7400 and IM-152 DP slaves. Communication between the PC and the PLC is via Ethernet. Control strategies are working ok.

The customer requires that the CPU LEDs be indicated in the operator graphics. We need to monitor the status of the CPU LEDS such as Run, Stop, Master, etc. If I can access those parameters and put them on a datablock, then there will no longer be a problem.

Unfortunately, I have trouble configuring SFC51 on a CFC chart. I created a shared datablock, and connect the datablock addresses to the SFC51's SSL_Header and DR parameters. I can't seem to get it working. I cannot even download the CFC chart program. I always get an error saying the interconnection of SSL_Header does not exist. The Simatic manuals confuse me. This is the only problem that I have and I hope someone could help me on this.

Questions:
If I am to start the configuration of SFC51, I need to create datablocks and connect the output terminals SSL_Header and DR to the datablocks addresses, right? If I am to read an H CPU module LED indications (I think SZL_ID of 0071, I'm not sure please correct me if I am wrong), how should I configure my datablock to allot for the parameters SZL_ID and DR? I am doing it incorrectly because I get error when the cfc program is compiled.

What value should I put on SSL_ID and Index?

If there is a way to configure this whole thing without using CFC an function block, please advise.

A setp by step or a "for dummy" instruction is I believe would be very effective. Need details so I can compare my current configuration with your suggestions.

You guys are my hero.

Thanks so much for your help.

-Chris

I don't have H-CPUs at hand, so I can't check it but seems to me that you have to call SFC51 with SSL-ID w#16#0074 nad Index w#16#0. Then SFC returns 19 (? - this I'm not sure) records 4 bytes each. To check number of records try calling SFC51 with SSL-ID w#16#0774 first - not sure if it works.

Need to confirm

Hi Jacekd,

Let me see if I get it correctly. This is how I interpret everything:

In OB1, I call SFC51. The value that I will enter for SSL-ID is W#16#0074 and Index is W#16#0. The 4 bytes of data goes to datablock address ot flags such as MB10.0.

Am I right? Please advise.

What do I do with the output terminal SZL_Header? What is the value that I should enter?

Thanks for your help.

Well, there's stated in manual that SSL_Header parameter cannot be written to areas other than datablock or local data.
In datablock or local data you should create SSL_Header structure (format is described in system function manual). Then SSL_Header parameter assignement should look like DBx.SSL_Header or (in case of local data) p#SSL_Header.
DR parameter can look like p#M10.0 byte 76(?) - I'm not sure if 76 bytes in enough in this case. But you can observe RET_VAL and if it's value is w#16#0081 when the SFC call is finished it means that 76 bytes is not enough.
And don't forget that SFC51 is asynchronous when writting your program.