OD DAQ Electronics Upgrade to Version 2 on 8/1/96
rev. 9/3/96
Note: For faster access at a Japanese location there's a
mirror
copy of this document available at the SuperK experiment site in Mozumi,
Japqan.
During the 1st shift on Thursday, 1 August 1996 (JST), HGB upgraded the OD
DAQ electronics. This upgrade included:
- replacing all current UWa custom boards (level 0 prototypes with
hand-wired patches here and there) with newly designed and commercially
etched PCB boards.
- Most of the cables for signal distribution from the center hut to the
outer huts were also relaced.
These cable and board changes affect timing and calibration.
The t0 (trigger reference signal) delay to the TDC inputs has been changed.
In reference to the global trigger output at the VME TRG module in the
central hut, the theoretical numbers for the old setup are (sorry, don't
have valid scope measurements on hand):
- for huts 1 + 2: 215 nsec +/- 15 nsec
- for huts 3 + 4: 290 nsec +/- 15 nsec
The new delays are (measured with a digital scope):
- 280 nsec +/- 10 nsec for all huts (cables are now identical!)
Run 2393 was the first valid run after the upgrades took place (during
second shift 8/1/96).
Here more details about the new boards:
In principle, the new boards are functionally completely equivalent to
the old versions. So, with the right jumper setting they'll run with the
current collector software without any change.
The new added features are:
- Improved connectors, e.g. latching header connectors with polarizing keys,
keyed modular connectors.
- More diagnostic LEDs, such as event number display, Fastbus TR0/3/6/7
status, etc.
- Un-inverting the event number signals (the old version, for reasons no
longer relevant, inverted the event number signals), so software can be
cleaned up and be more readable. Implemented 8/2/96.
- Event number 'chopping' (for the free
TDC channels) moved from a central distribution in the center hut to
individual 'chopping' in the outer huts. In the previous version, the
long distribution cables (100'/150') to the TDC inputs caused signal
deforming which were then misinterpreted by the software as pulses at
the wrong spots. The new, local distribution solves this problem by
using the shortest possible cables (20" only) to the TDC inputs.
- Choice of event number 'chopping' and t0
signal shape, jumper settable at the new Fastbus boards, either to
current version (logic 'AND' with global trigger / t0 = global
trigger) or to single-edge only, using the rising edge of the global
trigger as reference.
- Improved TDC stop/Struck stop veto handling:
- adding a VME-addressable veto signal, e.g. to avoid triggering the
TDCs during a FSCC reset/boot period, which caused us lots of trouble
previously. Tested 8/2/96, but not yet implemented in software.
- stretching the BIP veto by another 200 nsec. Jumper settable, but
not activated yet.
- improved global trigger rising edge detector: When a veto period
ends right after a new global trigger has started, but the trigger
signal is still logic high, it will also be rejected for the
TDCs/Strucks and the system will instead wait for the next trigger.
- Adding a separate 'end-of-BIP' trigger output for future plans to use
separate Fifos (V533) for the global triggers and BIP triggers.
- 3 more VME programmable LEMO outputs, jumper settable to either NIM or
TTL level.
- Added 2 inputs for TDC calibration signals (common start + clear) from a
central source in the center hut.
- Test trigger pushbuttons, so the user can invoke single test
triggers from all 5 huts to the whole OD DAQ system. When pushing one
of these buttons, a veto signal blocks global triggers for a brief
period (adjustable from 15 to 400 msec).
- Fastbus power supply monitor. Warning beeper and red flashing LED as soon
as any of the 5 voltages is not within +5%/-8% of its nominal value.
Cabling upgrade:
The cabling between the center hut and the outer huts was upgraded
at the same time.
These are:
- Replacement of the FSCC-AUX-to-DC2 data bundles for huts 3 and 4
from 150' solid (easy breakable) multiconductor cables with non-latching
connectors (misalignment happened sometimes) to 120' flexible
'twist+flat+jacketed' cable with latching connectors.
(Huts 1 and 2 were already hooked up with the same type of cable in
February)
- Replacement of the Event number distribution cables for the OD DAQ in
all 5 huts with jacketed cable.
- Replacement of the 'BIP' cables (150' each) with new flexible LAN-type
cables (125' each) and latchable, orientation-keyed modular
connectors.
(The BIP cables distribute the TDC common stop, Struck latch
trigger, and FSCC remote reset signals from the center hut to the outer
huts, and run the TDC busy [BIP] signal back to the center hut)
- Adding a 'CAL' cable from the center hut to each outer hut. 125' long
- i.e. same length as new 'BIP' cable (to match the signal timing) - and
a keyed modular connector at each end (so the user can't mistakenly
interchange the cables).
These new cables distribute the global trigger pulse and two
user-defineable calibration signals (e.g. TDC common start, TDC clear)
to the outer huts, plus a test trigger feedback signal back to the
center hut.
additional documentation
Fastbus Power Supply manual
UW group's inventory list of items at
SuperK
Ken
Young's outer detector DAQ documentation
SuperK US collab
homepage
For further details see the updated OD DAQ documentation.
Questions? Send email to
berns@phys.washington.edu.
