s7 1200 alarm set up

[alexmcsheffrey]

Hi can anybody give me some advise on setting up the alarm page on the s7 1200 plc and basic hmi.I have set my alarm word to mw150 and have a input setting a alarm bit m150.1.i have set the alarm trigger in hmi alarms to the tag associted with mw150 and set the trigger to 1 and entered a message.I also have put the alarm view on a hmi page.
problem is when i set the alarm bit m150.1 on in the plc there is no message in the alarm view??

 

[504bloke]

Are you sure M150.1 is HIGH ?

Are you sure M150.1 is the alarm bit you specified ?

(I dont use the basic HMIs as i dont like them so cant offer help on the setup of these!)

Did you read the help files for alarms as they are pretty good ?

 

[alexmcsheffrey]

Hi checked all and all okay checked hmi alarm help file and all looked okay?

 

[Pego]

Set the trigger bit to 9, bit 1 of the next byte.

Have a look here: http://en.wikipedia.org/wiki/Endianness

 

[alexmcsheffrey]

thanks will try that am i right in thinking the alarm bits are taken from the next byte then not the first 8 bits of the first byte??

 

[Pego]

The low and the hight byte of a word are exchanged in the Endian notation used by Siemens.
That goes back to "the old days" as you can read in the link.
I just don't understand why Siemens does not "hide" this "problem" by letting the Step7 software do the exchange.

 

[HJTRBO]

Also check to see the alarm window is set to display automatically and that the alarm window is inserted into the global screen if you want it to display on all screens.

Tangent hijack Q to Pego [Apologies OP]: So are we "Middle-endian" based here in Siemens world???

 

[Pego]

http://www.plctalk.net/qanda/showthread.php?t=41038

 

[alexmcsheffrey]

thanks Pego worked no problem, simple when you know that as you say though cant understand why siemens would do it that way have m150.0 in your ladder but be trigger bit 8 in you alarm register.I am trying to sort out the time/date stamp on the alarm register to be as is, struggling to find how to do it ? any advice??

Regards
Alex