FP write On Change Terminal

[Golzio]

Hi all,
as shown in the attached picture I use the FP Write.VI
with the ON CHANGE terminal set TRUE. Testing the attached code I verify that often my output remains TRUE even if the code write FALSE. This happens only with the ON CHANGE terminal set TRUE.
Any hint will be usefull.

Thank you
Alessio Colzi

[Aaron_G]

Alessio,

The On Change input is used to tell the FieldPoint server to only write data when the data has changed. The data change is done by comparing the last value written to the current value input. However, this comparison is done on the data input to the VI directly and does not differentiate between different Tag names. Thus, in the code that you have posted (the FOR loop indexing through multiple tags), the On Change does not appear to work because it is comparing the last value written to the last channel vs the current value to be written to the current channel, it is not comparing the current value to be written to the current channel vs the last value to be written to the current channel. In order to use the On Change Input, you will need parallel ex
ecutions of the FP Write.vi and can not auto-index through multiple tags into the FP Write.vi.

Regards,
Aaron

[Golzio]

Thank you for your help,
I have a lot of fieldpoint module output to write and so I have a global variable where I store all the output (every row is a module). According to your reply I can write code to make the "FP Write" only if a row is changed. Is this a good approach in your opinion?? Have you any advice for users that needs to manage a lot of fieldpoint output module (for example how to manage error from a single module)??

Best regards
Alessio Colzi