Temperature monitoring

[Simon Taylor <staylor@jlab.org>]

Hi, all.

Since the preamp chips on the daughter boards will be in a confined space
and will start to get warm, in addition to devising a cooling mechanism we
have been considering adding thermistors to the preamp boards so that we
can monitor the temperature.  I have discussed this idea with Fernando
Barbosa and together we have come up with an alternate scheme that should
be readily expandable to sensors other than temperature probes and could
be used to monitor the environment near other detector components in
addition to the FDC.  The idea is that we would have multiple small sensor
boards on the order of 1/2" x 3/4" in size and equipped with sensor chips
that could be mounted wherever we need to monitor the
temperature/humidity/etc.   Digital signals from these boards would be
distributed through an intermediate "power and signal distribution" board to
VME modules that we would use to input the signals into the data acquisition
every 10 seconds or so.  A cartoon of the idea is attached.   This offers a
flexible solution for slow controls/monitoring that does not unnecessarily
complicate the design of the preamp boards.  The temperature sensors would
instead be mounted near the preamps in a manner that would need to be
worked out (we just started working on this idea).   A possible
temperature sensor chip we could use (identified by Fernando) is the ADT7484A,
which costs about $1.50 each.

Simon

slow_control_hardware.pdf