blank_page
Hi all! Now, for the question I have, the answer really
should be simple, but the bugger eludes me! 😞
To put things very simply, 😉 my aim is to heat a vessel up
to a pre selected temperature. Once at that temperature, a timer should allow
the temperature to continue for the predetermined time, then switch off the
heater until I press the reset switch or restart the heating process.
The temperature (centigrade) is dialed in and so is the
time (in seconds). I have a few more bells and whistles, of which do not affect
these. This is my aim in its simplest form! 🙂
My problem however is the darned timer. I actually have a
number of vessels to heat, each one independant in thier own little case
structure all withing one while loop. The ON switch is inside the while,
outside of it's relevant case structure.
I have tried various types of 'logic' gate timers, and am
currently fiddling with 'elapsed time' vi. The problem is however that the
countdown (I have an indicator showing this - well more of a count up) starts
instantly if the 'elapsed time' vi is withing the heating case structure,
whether it's in it's own secondary case structure or not. If it is outside the
main case structure for that heating sequence, it freezes / doesn't work if in a
case structure, and goes of it's own free willl if not in a case structure, but
still between the main case structure and the while loop.
On the elapsed time, I have a 0 (zero) value (in a blue
box) wired to 'set start time (s)'.
The selected time value is wired to 'time target (s)'.
Elapsed time from the vi is wired to a greater or equal
function, of which compares the time elapsed to the time required. This in turn
is wired to a case structures acting as relays of which should turn off the
heating and allow an indicator to display 'reaction complete'. This 'reaction
complete' does in fact light up, but goes off again as the timer starts it's
loop / cycle again. Ideally the timer would stop here and a reset or restart
would re initialise the entire sequence.
My question is, does anybody have a vi that I can use to
start a time sequence initiated by a required temperature, of which is 'held' at
that temperature for a set period of time, before turning off the heater. This
should ideally be able to be placed in a pre existing while loop, of which helps
facilitate the reset function (when reset is pressed, the timing is reset ready
to start again from zero).
For this I use a 7.1 system (havn't set up the v8 yet)
programmed to a cFP 2020. The touchscreen is a Qlarity G75. The G75's will
probably not show up on the attached vi for most people, but things can still be
followed easily I hope. When viewing the attachment, focus on the VESSEL 1
area. All the way from left to right 🙂
Hope someone can help!
regards,
Steve
- oh I have attempted to add the vi as an attachment, with notes to
explain what is going on at which point. It shouldn't really be needed, but may
be of some use with the above text. However as I am using a USB wireless broadband in Borneo, I may have to post it seperatly if the upload takes too long on this attempt!
