varying alarm limits at different intervals

[desire]

Hi All.

I am using LABVIEW 8 and D515 datalogger. i am getting temperature from10 thermocouple inputs. i take avarage of these temperatures and log them on an excel sheet. i am getting temperature readings after every 25 seconds and log data for 6 hours. this is a refrigeratin system and over 6 hour time span my temperature drops from 30 degree to 3 degree. now i want to add an alarm in a way that it has a variable upper and lower limits. for example for 25th reading temperature upper and lower limits will be 25 and 22 degree respectively and for 50th reading these limits will be 24 and 21 degree respectively and so on. (please refer to figure attached). In this way i will get a check that my temperature is falling with desired rate, please let me know how i can implement this? if there is any example code that can be of any help please let me know. i am new labview user so please reply in a simpler way. thankyou.

                                                                        Hamid

[Chris_Cilino]

Hamid,

Boy have I got some great news for you. There is an express vi called "Mask and Limit Testing" that I think will do exactly what you're looking for. Help for it can be found at here. Post to let us know if this helps!

Chris C