<!-- Title: 18:23:26  Tue Mar  9 2004 -->
<!-- Crewchief: Pulsar folks -->
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<pre>We have recovered the previous Pulsar e-log (see previous page). 
In that page, one can found all the details on the hotlink 
splitting testing results. we will start a new page here.</pre>


<!-- Date: Tue Mar 9 18:37:30 2004 -->
<pre>Here is a summary on the muon hotlink fiber splitting studies: 
 
(1) we have measured all optical power at muon (pre)matchboxes 
outputs as well as the inputs to the L2 muon Pulsar boards. 
We found two problem fibers and replaced them with two spares. 
After that, all power reading seem to be fine (according to 
power meter). 
 
(2) we also found one bad short fiber from the splitter box 
to the L2 muon Pulsar crate and replaced it with a "white" 
fiber. 
 
(3) two channels (channel 1&5) failed in the beam test 
when all fibers are splitted. 
 
(4) we have tested carefully our hotlink receivers on one 
Pulsar board as well as the official Pulsar board in the 
L2 decision crate, with additional attenuation. Turns out 
that all of our receivers can handle 24dbm input power without 
problem (note the hotlink Tx output is typically 16+-1 dbm). 
Most of them (except one) can also handle 28dbm input power 
with Tx--&gt;Rx DAQ tests... 
 
(5) more careful studies were done at Ted's office with 
hotlink Tx --&gt; Rx in BIST mode, with additional attenuation, 
and catch the RVS (hotlink receiving violation signal) on 
scope. This setup can catch any error with much high statistics 
as the hardware checks the error on-the-fly. The results 
show that there is no problem with 24 dbm, and at 28 dbm,  
it takes a while for receiver to have errors. Data sheet 
shows that the minimal input power should be about 26 dbm,  
so this is not surprising. What this means is that 
with one purple splitter, we have 20 dbm power after splitting, 
so we should at least have 4-6 dbm safty margin.  
 
(6) after all these studies, we still do not understand 
why there were two channels failed the beam test with splitting. 
we need to think harder.</pre>
<!-- Author: Burkard and Ted -->
<!-- Comment: Tue Mar  9 22;45;13 comment by...Ted -->
<pre>power meter measurement indicates that the muon matchbox Txs
are ok for channel 1&5, while Pulsar Tx--&gt;Rx test indicates
that Pulsar receivers for channel 1&5 are ok. so we still
don't understand why channel 1&5 failed in the beam test
after muon fiber splitting. since power meter only measures 
the power on average, the next thing we should do is to swap 
channel 1&5 with other channels which we know work with
splitting, and see if the problems stay with the receivers,
or follow the fibers (tx). this should help us to find out
what caused the problem in the beam.</pre>
<!-- Comment: Wed Mar 10 20;49;16 comment by...Burkard/Cheng-Ju/Ted -->
<pre>Tonight we finally understand the muon splitting problem after
we have done the swaping channel exercise described above.
Turns out the problem follows the fiber: i.e. the cause of the
problem was due to a problem/weak Tx downstair. In addition,
we have scanned all 16 channels with 2 purple splitters daisy 
chained to get additional attenuation to find the "edge" and to
see what kind of safty margin we have, and compare that with
the results from lab test with Ted's office setup.


(1) understanding whether it is the driver or receiver:

for this test, we take two channels: channel 1 (which failed
in beam test with one purple splitter) and channel 3 (which
was ok in beam test with whitebox SVX splitter). For each
channel, we added two purple splitters daisy chained for each,
so that we can "force" channel 1 to fail with cosmics while
channel 3 is still fine.

then we swapped the two channels, and our Muon TrigMon allows us
to swap channels with tcl talk to and this made the test much
easier. After we swapped the two channels, the problem follows
the fiber, not the receiver! this is a clear indication that
the problem is at the Tx side (downstair). Now what about 
channel 5? we did the same thing and channel 5 is ok with two
purple splitters. Note that channel 5 was splitted with one
whitebox splitter (~7-8 dB) in the beam, that is why it failed
in the beam and not in the cosmics with two purple splitters.

According to the test results in Ted's office runing hotlink
in BIST mode, the Rx will fail only with input power at around
~26 dBm or less. so we decide to reproduce that result with 
the system in cosmic run condition by scanning through all 
16 channels with two purple splitters. Here are the results 
and they are in perfect agreement from lab test:

ch:   input power after two purple splitters daisy chained:

00    24.21  ok
01    25.48  failed
02    25.20  failed
03    24.74  ok
04    24.17  ok
05    26.05  failed
06    23.49  ok
07    25.30  ok
08    24.60  ok
09    24.68  ok 
10    25.86  ok
11    24.59  ok
12    24.98  ok
13    24.17  ok
14    24.79  ok
15    23.83  ok

note that there is a clear pattern that once the power is 
in the range 25-26 dBm, it will have a good chance to fail.
while for channels which receive high input power (24dbm or so)
they all pass the test.

the only puzzle is that for channel 1, we measured a few days
ago that its output power (tx downstair) is about 18.54 dBm,
and it is lower than the others (so is channel 5). with one
purple splitter, it will have about 22 dBm. this shouldn't fail
the beam test based on our current understanding. yet it indeed
fails both beam test and the tests above and this is independent
of the receiver. We therefore conclude this particular Tx is
not "so good", and will recommend to Eric to replace it 
(Eric will be back soon). and we may want to
replace channel 5 as well as it also has a lower power reading.

Based on what we have learned in the past week with extensive
studies on the splitter problems, we believe that once we replace
the two optical drivers, we should be able to split muon with
purple splitters without problem (note also that with one purple
splitter, channel 1 can pass L2 torture runs).</pre>
<!-- Comment: Fri Mar 19 15;30;20 comment by...Burkard -->
<pre>Eric James took two optical transmitters from spare boards and
replaced the "weak" transmitters on two boards (MB 02 & MB 05)
upstairs at the output of the muon fiber (no splitter) I now measure 
15.33 (MB 02)
16.52 (MB 05) 
Now we are preparing a cosmic runto check the functionallity of the
Muon MatchBox boards, before we try splitting.</pre>
<!-- Date: Tue Mar 9 18:46:43 2004 -->
<pre>Here is stuides done on Taxi. So far I have done the following: 
 
(1) measured the optical output power on all our Taxi Tx Pulsars, 
to get some idea on the distributions. The typical output 
power at Tx has a range from 15-20 dbm. This is quite different 
from hotlink case (Tx typcially has 16+-1 dbm). will post 
the results next. 
(2) measured the optical power for all RECES channels at 
the input to the RECES cards in the L2 decision (with Masa). 
will post the results next.  
(3) with Taxi Tx--&gt;Rx in the setup at my office, measure 
at what input power level Taxi receiver will pull "receiving 
violation signal". This test is on-going. 
</pre>
<!-- Author: Ted -->


<!-- Date: Tue Mar 9 18:58:53 2004 -->
<pre>Optical output power measured on some of our Taxi Tx Pulsars. 
 
(1) Pulsar Taxi Tx in the top crate in the teststand room 
(i.e. Vadim's Isolation Tx. channel counts start from top) 
measured at the Tx output with a reference cable: 
 
channel 0: 17.40 dBm 
        1: 16.71 dBm 
        2: 18.67 dBm 
        3: 17.20 dBm 
        4: 18.66 dBm * 
        5: 18.84 dBm 
        6: 17.75 dBm 
        7: 17.68 dBm 
* note: I also checked the power at the inputs to the Taxi Rx. 
  I found that for channel 4, the fiber in that setup gives 
  only 24.46 dBm. Vadim, you should check this fiber! 
 
(2) Taxi Tx in the trigger room (Pulsar crate, Vadim's cluster Tx): 
 
channel 0: 13.96 dBm 
        1: 19.20 
        2: 14.31 
        3: 14.36 
        4: 13.69 
        5: 14.23 
        6: 15.81 
        7: 19.51 
 
 
(3) RECES Tx in the XFT lower crate (i.e. Chris's setup): 
 
channel 0:  17.20 dBm 
        1:  16.64 * 
        2:  17.02 
        3:  18.19 
        4:  20.14 
        5:  19.39 
        6:  19.76 
        7:  20.31 
        8:  20.06 
        9:  20.03  
* note: I also measured on the Taxi Rx end in this setup. 
and found that the fiber for channel 1 is likely bad, 
as the power reading on the rx end is only ~27 dBm... 
Chris: check this fiber! 
 
overall, the spread of Taxi Tx power is in the range: ~14-20 dBm. 
This is a rather wide spread. So now, we know what we expect 
from the Txs, it is time to measure the actual RECES system to 
see how much optical power we have at the RECES inputs.</pre>
<!-- Author: Ted -->


<!-- Date: Tue Mar 9 19:12:24 2004 -->
<pre>Here is the results Masa and I measured at the RECES input 
stage (with the same reference cable used in above measurements). 
Note that there are three fibers already splitted with purple 
splitters: East 2: 8/9/10 (the ones with "*"). 
 
      West 1          West 2            East 1           East 2 
 
ch 0  15.20 dBm        15.50            15.91             15.56 
   1  16.94            16.86            17.01             15.47 
   2  17.74            19.41            17.01             15.73 
   3  14.67            16.00            16.44             15.47 
   4  19.15            15.12            17.62             18.35 
   5  13.22            17.07            18.82             15.52 
   6  17.45            17.21            16.55             19.30 
   7  15.33            15.69            19.07             15.68 
   8  16.42            18.29            17.90             18.66* 
   9  15.08            14.82            16.15             19.27* 
  10  17.20            16.53            18.20             21.22* 
  11  17.89            17.20            18.40             19.80X 
 
X Note: Masa told me that Chris tried to splitt channel 11 on 
East 2, and it failed... this one power meter reading is 
19.80 without splitting, with purple splitter, it will have 
about 24 dBm... this is something to keep in mind.</pre>
<!-- Author: Ted  -->
<!-- Comment: Thu Mar 11 17;48;48 comment by...Ted -->
<pre>Here is a summary of the lab test results for Taxi:

the setup:  

Taxi Tx --&gt; ~4dB splitter--&gt; ~ 4dB splitter(or bypass)--&gt; Rx --&gt; 
watching the VLTN signal and trigger on scope.

VLTN signal is the receiving violation signal for Taxi. The
Tx output power has a range ~14-20dBm (by selecting which Tx
channel, I can select the power before the 1st splitter).
after the 1st splitter, the power range is ~18-24dBm. By using
a 2rd spitter, the range can be varied between ~22-28dBm. 
Here is a summary of test results:     


(1) at ~20 dBm, Tx --&gt; Rx runs without problem
(2) at ~23 dBm, error occurs in ~ 1 hour or so
(3) at ~26 dBm, error occurs in a few mins
(4) at ~28 dBm, error occurs in seconds...

The 50 um SVX/SVT splitter (whitebox) were used for 
Isolation splitting long ago, it typically has ~7 dB 
attenuation with 62.5 um fiber. This means the delivered
power after splitting at the receiver input has a range
of ~21-27 dBm. No wonder earlier attempts to split Iso
fibers failed.</pre>
<!-- Date: Thu Mar 11 13:58:32 2004 -->
<pre>Re-did Taxi Tx-Rx tests in b0l2pu00 in order to debug problems 
previously seen on Tx channels Data IO 1,1 and Data IO 1,2. 
We saw these problems when running in this trigger room crate 
twice, once in January and once a few weeks ago. 
 
Cannot reproduce the problem today.  A couple things changed: 
 
       o ID'd and discarded one bad fiber (used on different  
channels) 
       o switched Rx mezzanine card (for these channels, but  
likely not culprit) 
 
 
I would not have thought the new mezzanine card would not have  
any impact because we did some fiber swaps the last time this 
test was failing that inidicated the problem was on the Tx  
mezz card. 
 
I am puzzled.  Will swap back the old Rx mezzanin card later in 
an attempt to reproduce the errors. 
 
 
Important news: Taxi Tx-Rx pair for now resident in b0l2pu00. 
I am running a Tx-Rx test at 2.5kHz L1A rate in order to  
accumulate stats, pumping patterns through.  I'd like to  
run this test overnight at least, longer if possible.   
 
Things are getting crowded in that crate; I foresee moving my Tx  
board back to teststand if I have to, but the Rx board stays for  
commissioning of stage0 of the splitting of XCES. 
</pre>
<!-- Author: neu -->


<!-- Date: Thu Mar 11 15:11:45 2004 -->
<table><tr><td><a href=/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-27&button=yes target='xxx' onclick='jswindow()'; align=top><img src=/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-27  width='300' align='top'></a></td><td>test setup to understand fiber splitting issues with 
both hotlink and Taxi </td></tr></table>
<!-- Author: Ted -->


<!-- Date: Thu Mar 11 15:26:19 2004 -->
<center><a href='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-30&button=yes' target='xxx' onclick='jswindow()'><img src='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-30' width='300'></a><a href='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-31&button=yes' target='xxx' onclick='jswindow()'><img src='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-31' width='300'></a><a href='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-32&button=yes' target='xxx' onclick='jswindow()'><img src='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-32' width='300'></a><a href='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-33&button=yes' target='xxx' onclick='jswindow()'><img src='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-33' width='300'></a><a href='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-34&button=yes' target='xxx' onclick='jswindow()'><img src='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-34' width='300'></a><a href='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-35&button=yes' target='xxx' onclick='jswindow()'><img src='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-35' width='300'></a></center>
<!-- Author: Ted -->
<!-- Comment: Thu Mar 11 15;27;09 comment by...Ted -->
<pre>some photos for people to prepare their talk. more below.</pre>


<!-- Date: Thu Mar 11 15:32:04 2004 -->
<center><a href='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-36&button=yes' target='xxx' onclick='jswindow()'><img src='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-36' width='300'></a><a href='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-37&button=yes' target='xxx' onclick='jswindow()'><img src='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-37' width='300'></a></center>
<!-- Author: Ted -->


<!-- Date: Thu Mar 11 15:34:07 2004 -->
<table><tr><td><a href=/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-38&button=yes target='xxx' onclick='jswindow()'; align=top><img src=/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-38  width='300' align='top'></a></td><td>splitter box </td></tr></table>
<!-- Author: Ted -->


<!-- Date: Thu Mar 11 15:35:14 2004 -->
<table><tr><td><a href=/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-39&button=yes target='xxx' onclick='jswindow()'; align=top><img src=/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-39  width='300' align='top'></a></td><td>Pulsar crate in the trigger room as of March 11, 04.</td></tr></table>
<!-- Author: Ted -->


<!-- Date: Thu Mar 11 15:46:34 2004 -->
<center><a href='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-40&button=yes' target='xxx' onclick='jswindow()'><img src='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-40' width='300'></a><a href='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-41&button=yes' target='xxx' onclick='jswindow()'><img src='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-41' width='300'></a><a href='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-42&button=yes' target='xxx' onclick='jswindow()'><img src='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-42' width='300'></a><a href='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-43&button=yes' target='xxx' onclick='jswindow()'><img src='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-43' width='300'></a><a href='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-44&button=yes' target='xxx' onclick='jswindow()'><img src='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-44' width='300'></a><a href='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-45&button=yes' target='xxx' onclick='jswindow()'><img src='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-45' width='300'></a></center>
<!-- Author: Ted -->
<!-- Comment: Thu Mar 11 15;51;32 comment by...Ted -->
<pre>Old boys with toys</pre>
<!-- Date: Thu Mar 11 15:50:40 2004 -->
<center><a href='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-47&button=yes' target='xxx' onclick='jswindow()'><img src='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-47' width='300'></a><a href='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-48&button=yes' target='xxx' onclick='jswindow()'><img src='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-48' width='300'></a><a href='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-49&button=yes' target='xxx' onclick='jswindow()'><img src='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-49' width='300'></a></center>
<!-- Author: Ted -->
<!-- Comment: Thu Mar 11 15;52;31 comment by...Ted -->
<pre>young boys with toys</pre>



<!-- Date: Thu Mar 11 17:56:16 2004 -->
<table><tr><td><a href=/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-50&button=yes target='xxx' onclick='jswindow()'; align=top><img src=/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-50  width='300' align='top'></a></td><td>S-LINK AUX card with fiber adaptors</td></tr></table>
<!-- Author: Ted -->


<!-- Date: Fri Mar 12 18:33:29 2004 -->
<pre>Performed splitter tests discussed this morning at L2 Upgrade  
Meeting.  Here is what happened: 
 
   o Rob Harr gave me opportunity to swap fibers at ~5pm.  Had  
15 minutes to un-split 3 lines from before (East 2:8-10), install 
4 other purple splitters in rack, and then split 8 lines.  Does 
not sound like much but it really was alot to do in short amount 
of time. Roser helped; he deserves alot of thanks. 
 
   o Here are the lines that are split:     
 
        Fiber           Tx Power (dBm) 
        -----           -------------- 
        East 2:6        19.30 
        West 1:4        19.15 
        East 2:4        18.35 
        West 2:8        18.29 
        East 1:4        17.62 
        West 2:6        17.21 
        East 1:6        16.55 
        East 1:0        15.91 
 
 
   o short run (179871) showed a handful of unexpected single-bit 
errors on the following lines: 
 
       Fiber           Tx Power (dBm) 
        -----           -------------- 
        East 2:4        18.35 
        West 2:8        18.29 
        East 1:4        17.62 
  
but no unexpected errors on other channels. Other channels with  
known error rates behave as expected. 
 
    o NO CONCLUSIONS can be made yet w/o more statistics 
 
    o Going to leave the 8 splitters in for awhile to accumulate stats. 
 
     
</pre>
<!-- Author: neu -->


<!-- Date: Fri Mar 12 18:35:55 2004 -->
<center><a href='/elog/notebooks/l2upgrade/Fri_Mar_12_2004_183422.ps'><img src='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-52' ></a><a href='/elog/notebooks/l2upgrade/Fri_Mar_12_2004_183519.ps'><img src='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-54' ></a></center>
<!-- Author: neu -->
<!-- Comment: Fri Mar 12 18;38;47 comment by...neu -->
<pre>Single bit errors can be seen in 

    Phi wedge 4, bit 24   (East 1:4)
    Phi wedge 16, bit 27   (East 2:4)
    Phi wedge 20, bits 4,11   (West 2:8)

Need more stats...but at least there are not hot channels.  Yet.
Will leave splitters in and monitor.</pre>


<!-- Date: Sat Mar 13 16:48:18 2004 -->
<center><a href='/elog/notebooks/l2upgrade/Fri_Mar_12_2004_183422.ps'><img src='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-52' ></a><a href='/elog/notebooks/l2upgrade/Sat_Mar_13_2004_164758.ps'><img src='/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-56' ></a></center>
<!-- Author: neu -->
<!-- Comment: Sat Mar 13 16;56;48 comment by...neu -->
<pre>Another before(left) and after(right) picture of the mismatched 
XCES bits.

The before picture is from the same run shown as "before" in the
above entry.  The "after" picture here is from a new run from 
today with, again, small stats.  

One can see that there are low-level bit errors introduced by
the splitting on three channels.  The three channels with new 
non-zero error rates are in fact three split channels. Note that
these errors are occuring on different channels that yesterday's 
early results.

Still need more statistics to determine where the threshold is.
Will keep the splitters in until the shutdown begins.  

ADC counts look unremarkable to my untrained eye and I'll attach 
them below.  I will forward all these plots to Masa to get his 
expert opinion.


There is an ambient error rate in the Run 2A system.  Given
that reailty, and the potential difficulties of splitting, 
swapping optical hardware, swapping boards, etc., my question is
this: what is the error rate that we can tolerate?  </pre>


<!-- Date: Sat Mar 13 16:57:11 2004 -->
<table><tr><td><a href=/elog/notebooks/l2upgrade/Sat_Mar_13_2004_165704.ps align=top><img src=/cgi/elog/det-system-elog.pl?nb=l2upgrade&action=view&page=-58  align='top'></a></td><td> </td></tr></table>
<!-- Author:   -->
<!-- Comment: Sat Mar 13 17;00;09 comment by...neu -->
<pre>ADC counts for XCES.  We seek ~100% efficiency for large ADC 
counts.  Not sure if dips below 100% above 1500 counts are
normal, or are statistical fluctuations, or are real problems.
Small stats surely spoil the bin at ~3000.  What about the bins
in 1500-2000?  I am communicating with Masa about this very issue.
Let's see what the experts have to say.</pre>


<!-- Date: Mon Mar 15 13:51:16 2004 -->
<pre>Performed some optical power measurements for isolation: 
 
Channel                       Power (dBm) 
                   Meas'd at RX      Meas'd at Tx     Difference 
   0                    18.27           15.00            3.27 
   1                    18.21           17.63            0.58 
   2                    18.65           15.15            3.50 
   3                    17.95           17.78            0.17 
   4                    17.94           16.86            1.08 
   5                    19.41           18.58            0.83 
  Master                21.15           18.69            2.46 
 
 
If you believe these absolute numbers, then the above appear to  
indicate 3 pretty lossy fibers (0,2,Master) and two marginally 
bad transmitters (5,Master).    
 
Not sure what the error size is on the measurements.  Need to  
repeat a bunch of times to gauge size of error.   
 
Note that the optical meter we are using to make these  
measurements is a piece of crap.  It loses signal fairly  
frequently, ie, behaves as if there is no optical input.  You can 
recover from this state in a variety of unscientific ways.   
 
Wish list: new optical meter that works. 
</pre>
<!-- Author: neu -->
<!-- Comment: Tue Mar 16 08;47;39 comment by...neu -->
<pre>Optical meter works much better when it is sitting stationary on a 
bench or something and not being moved/handled.  The meter gave me 
zero problems yesterday afternoon in the trigger room when I was 
using it this way.

Also the meter gave no problems down in the collision hall where we 
kept it pretty stationary.</pre>