Reading multiple bits at once

I'm using Siemens S7.

I've an an alarm list of more than 2000 alarms stored from DBX0.0 to DBX379.7.

I'm accessing to the PLC with a software in order to read those alarms and I dont know how to read a lot of bits at once.

I know if you have for example the alarms stored in bytes, you can 100 alarms in a row by using:

DB2.DBB180$100

Click to expand...

Is there a way like this to read alarms stored in bits in a row?

Thanks in advance.

You can read up to 32 BOOLs at a time by using doubleword instructions.
For example


For 2000 alarms you need to duplicate the above code 62 times, or loop through the alarms using pointers.
For the latter, I think you need assistance from a more experienced programmer.

bte001 said:

I'm using Siemens S7.

I've an an alarm list of more than 2000 alarms stored from DBX0.0 to DBX379.7.

I'm accessing to the PLC with a software in order to read those alarms and I dont know how to read a lot of bits at once.

I know if you have for example the alarms stored in bytes, you can 100 alarms in a row by using:
Is there a way like this to read alarms stored in bits in a row?

Thanks in advance.

Click to expand...

What specific software?

For multiple words you could do:


Or you could write a function that receives a pointer to the alarm data That can then be used to determine the length and fed in to a loop analysing all data for any bit set.

Nick

The way the 1st post is phrased, I am betting that bte001 has no knowledge of Siemens S7, maybe he has knowledge of WinCC but not the PLC part.

Rereading the 1st post, I realise that bte001 probably means how to address many bits not in STEP7 but in "a software", and this "software" may be WinCC or some other HMI or SCADA.