[time-nuts] Tbolt and iCruse readout problem - any ideas?

Didier Juges didier at cox.net
Wed Aug 18 11:33:35 UTC 2010

When you say "will not display the DAC V value", do you mean the display is
blank, or it displays garbage?

Interestingly, the code that displays temperature and DAC voltage is
essentially the same, the only difference being which part of the data
string received from the Thunderbolt is processed, so it is hard to imagine
why one would work and not the other, unless the data received from the TB
is corrupted in the part that should contain the DAV value, and the
conversion routine fails.

If you have doubts that the serial interface may not be working (I am not
sure about what missing resistor you are talking about), fix that first and
try again.

Looking at the serial stream with a scope may help diagnose such problem.

Didier KO4BB

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of David Bobbett
Sent: Wednesday, August 18, 2010 4:23 AM
To: time-nuts at febo.com
Subject: [time-nuts] Tbolt and iCruse readout problem - any ideas?

  Hi all,

Having struggled in vain to solve this problem, I thought I  would make a
plea for help as my first posting to Time Nuts . . . so here goes!

I have a Tbolt with v3.00 firmware which works fine with the Tboltmon.exe
V2.60 and Lady Heather software. It also works fine with the iCruse Tbolt
LCD monitor - except that the monitor will not display the "DAC V" value,
all the other values are displayed without a problem. 
The iCruse is the later version which has had the PIC voltage conversion
done, but not the RS232 input resistor mods.

I have two questions really:

1) Is there a setting which I need to change in my Tbolt using Tboltmon.exe
to get this to work?

2) Does anybody on Time Nuts have an iCruse which shows a negative value for
the "DAC V"?

As far as I can see, there are 3 options: a) there is a configuration 
problem, b) the iCruse doesn't display negative values for DAC V, c) my 
iCruse is faulty. I've pretty much run out of ideas on this one, so any 
suggestions would be greatly appreciated!


David Bobbett, Milton Keynes, UK.

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