[ANSS-netops] episensor es-t isolated supply option

[mwithers at memphis.edu]

I wanted to make sure people are aware of the isolated supply option
Kinemetrics now offers with the episensor es-t.  It uses +12V instead
of +-12V.  You must, of course, make sure your cables are wired to
support it.  Ours weren't and it took us a while to figure out why
we were not getting a response from the episensor when connected
to a RefTek RT-130.  Changing the jumpers in the ES-T fixed the "problem."
So now we're looking at modifying the cables to take advantage of
the isolated supply.  Kinemetrics has a supplemental document
(301923.pdf) that provides details.

Along this note, we'd like to be able to use the ES-T in differential
output mode for the noise reduction.  Unfortunately the only options
here are 10Vpp and 40Vpp.  Our DAS is a Reftek RT-130 which wants
20Vpp on the input.  There is a 20Vpp single-ended option with the
ES-T but we'd really like to use the differentail mode.  So we're
thinking about setting it up for +-4g and 40Vpp so we get +-2g on
the RT-130 20Vpp input.  Has anyone tried this and does anyone know
what will happen in the unlikely but theoretically possible event that
we go over 2g and overdrive the + or - 10V input on the RT-130?

An alternative of course would be to install an antennuator but then
we have to make sure it zero phase response ...

Mitch

Center for Earthquake Research and Information (CERI)
University of Memphis                Ph: 901-678-4940
Memphis, TN 38152                   Fax: 901-678-4734