how to find alarm location using siemens s7 semitic?

search for the tag location and find where you write to it

Hi..In most cases,it depends on the configuration of the PLC/HMI..You can have a Siemens Plc(S7) and have a different vendor for the HMI...The procedure for Locating the Alarms are not the same..Do you have a HMI PC from another Vendor?...In Most cases the Data exchange between Siemens PLC and HMI is carried via TAGS...so a Global Data Block was declared on the Program Structure..Does the Alarm have Codes?(Numbers)...If so,It can easily be located on the S7 program...

Most HMI's operate on a client server basis. The PLC is the server and the HMI the client. So it is the HMI that askes for the alarm point. There are many ways to program alarms and the location is the word address from inside S7. S7 uses byte addressing which can be easily seen in the simatic programming environment.

Now if you are talking about system alarms, these are handled through the interupt routines. If memory serves me right, the S7-300 handlers are the system routines in the OB90's and the S7-400 are the OB80's. The interupt OB offers up a data structure and the fault codes are in there. It is best to read the instruction manuals as it is a bit complex, but there will be programming required. I usually manipulate that codes and put them into an M register, which is one of the few good uses for the old M registers these days. By the way, one should aways place these OB's in their program, even if there is no code in them. Otherwise a fault such as a loss of an I/O card shuts down the processor.