The bit that was recently used to carry the spin flipper
information is part of a pit pattern that is being set
by the ABS control software 'ABSsoft'. In this software
you set all 16 bits with one command. One bit, the one
now used for the spin flipper, was redefined for this
purpose without undoing the control that existed in the
ABS software. This means that the spin flipper is using
a bit that is actively controlled by the ABS software
every time the target flips during the run or transitions
are scanned etc. unless you mark it with an 'x'. This
was done by Vitaly today. But this can only be a temporary
solution and is not safe as we can see in the present
case.
A better way is to have the out-register that Tylan
mentioned send a TTL signal to the in-register that Karen
mentioned and have independent control of ABS and spin
flipper bits.
Hauke
On Friday, February 27, 2004, at 05:15 PM, Tancredi Botto wrote:
>
> hello...
> sorry I had a busy day.. I agree with taylan, and btw we
> discussed at various points the need for an epics "summary"
> variable for the beam helicity after the experience of last year.
>
> It seems that problem is
>
>> when target flips it resets this bit. It is
>> reminence of the time when this bit was Nitrogen
>
> is this a feature of ABSsoft such that when the target flips all
> bits on the input register flip or is it simply how the flip
> sequence was programmed ?
> The problem of last year occurred when we were flipping the beam only.
> It had to do with the fact that if a run was started midfill after a
> spin flip, that run started non flipped.
>
> I don't see a problem of sending a TTL from compton directly to
> rack 3. Even less so if there is a spare in the patch...
>
> regards,
> -- tancredi
> _______________________________________________________________________
> _________
> Tancredi Botto, phone: +1-617-253-9204 mobile: +1-978-490-4124
> research scientist MIT/Bates, 21 Manning Av Middleton MA, 01949
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