PSN-L Email List Message

Subject: Re: My broken DataQ AD converter
From: "tchannel" tchannel@..............
Date: Sat, 31 Mar 2007 13:29:46 -0600


Well Chris, You did it again!  I hope your head doesn't get too =
big.....But facts are facts. From way over there, in the UK?, you were =
able to help me fix this silly AD board, here in Boise Idaho, USA.......

I do believe you were correct at every turn....

1  I do think this is an older 194 8 bit board, from your physical =
description.
2  The resistor numbers on the surface mount components were 1003, and =
2003.  Of course the two missing ones had no numbers.  But there was a =
pattern as the resistors were in a row, something like =
1003,2003,1003,2003,1003,2003,xxxx,2003, so I figured the xxxx was the =
1003, 100K
3  The other missing resistor was near others which had the 2003, so I =
figured the xxxx would be a 200K, the way it is built I could not see =
where these resistors were in the circuit.  I soldered in the two =
missing resistors, and it is now working!!!!!!!

4  I did go to AmaSeis .ini files but did not see any "Channel # listed" =
 so maybe it is always going to be Channel 1.
and never Channel 2,3, or 4.
5  I do think you are correct about someone modifying the board to run =
as a +5v and a -0, as these two missing resistors just did not fail and =
fall off, they look like they were purposely popped off, small scratch =
marks in their place.

Again, Many Thanks, Ted

  ----- Original Message -----=20
  From: ChrisAtUpw@..........
  To: psn-l@.................
  Sent: Saturday, March 31, 2007 12:00 PM
  Subject: Re: My broken DataQ AD converter


  In a message dated 2007/03/31, tchannel@.............. writes:


    Hi All, Looking closely at the board I see two resistors which are =
"Open" "cracked"
    Its a wonder it works at all, but some parts of it do work. Channel =
1, only puts out + voltage, just a small amount of -
    I think that account for the AmaSeis trace showing only the top part =
of an earthquake.


  Hi Ted,

         The input resistors are two 200 K in series. The offset line is =
100 K to the centre point. If any of them are damaged, it should not be =
difficult to replace them. Alternatively, could you  unsolder the =
resistors on CH4 and replace the ones on CH1? The resistor values are =
printed on them eg 2003.
         I get about -0.59 V on the offset line and about 90 mV on the =
input. I suspect that this is because the ADC is not in operating mode. =
The offset line should be -5V for +/-10V input. Check the voltage on the =
offset line while the channel is switched on?


    However Channel, 2,3,4 all seem to work showing both positive and =
negative movement "In DataQ Software Only", in this software Channel 1, =
only shows positive trace movement, and, no negative.


         You could get this with failed resistors. Is the range 5V or =
10V? I suspect that the ADC may have been 'modified' for a single =
polarity 5V signal? Can the friend who gave it to you provide any =
information?=20


    When I connected my Sensor to Channel 2,3 or 4 Using DataQ,  I was =
thinking it would then work in AmaSeis, but it does not.  It looks as if =
AmaSeis will not read any Channel except Channel 1. Even though in DataQ =
Channel 2,3,4 all seem to work fine.  If I connect the sensor to Channel =
3,  AmaSeis shows a trace, but the trace does not move in either =
direction if I stimulate the sensor.  This is true for Channel, 2,3,4.  =
Only Channel 1, moves the trace in AmaSeis.
    I think you can change the com port, in AmaSeis, but is there =
anywhere you can or need to change for Channel selection?
    In DataQ I closed all the Channels except Ch. 3 and saved before =
closing.  So If I were just using DataQ software, I would be =
operational.


         Amaseis normally uses CH1 only. However there are two setup =
files Amaseis.ini and AS1.ini. It may be possible to set a different =
channel by editing and then saving the file, but I am not sure. I know =
that you get your different sample rates this way. If you use a Dataq =
and Amaseis without editing the ini file, you just get 6 SPS.

         This information is taken from an old 8 bit DI-194 board, which =
I suspect that you have.

         Regards,








Well Chris, You did it again!  I = hope your=20 head doesn't get too big.....But facts are facts. From way over there, = in the=20 UK?, you were able to help me fix this silly AD board, here in Boise = Idaho,=20 USA.......
 
I do believe you were correct at every=20 turn....
 
1  I do think this is an older 194 = 8 bit=20 board, from your physical description.
2  The resistor numbers on the = surface mount=20 components were 1003, and 2003.  Of course the two missing ones had = no=20 numbers.  But there was a pattern as the resistors were in a row, = something=20 like 1003,2003,1003,2003,1003,2003,xxxx,2003, so I figured the xxxx was = the=20 1003, 100K
3  The other missing resistor was = near others=20 which had the 2003, so I figured the xxxx would be a 200K, the way it is = built I=20 could not see where these resistors were in the circuit.  I = soldered in the=20 two missing resistors, and it is now working!!!!!!!
 
4  I did go to AmaSeis .ini files = but did not=20 see any "Channel # listed"  so maybe it is always going to be = Channel=20 1.
and never Channel 2,3, or = 4.
5  I do think you are correct = about someone=20 modifying the board to run as a +5v and a -0, as these two missing = resistors=20 just did not fail and fall off, they look like they were purposely = popped off,=20 small scratch marks in their place.
 
Again, Many Thanks, Ted
 
----- Original Message -----
From:=20 ChrisAtUpw@.......
To: psn-l@..............
Sent: Saturday, March 31, 2007 = 12:00=20 PM
Subject: Re: My broken DataQ AD = converter

In a=20 message dated 2007/03/31, tchannel@..............=20 writes:

Hi All, Looking closely at the board I see two resistors = which=20 are "Open" "cracked"

Its a wonder it works at all, but some parts of it = do work.=20 Channel 1, only puts out + voltage, just a small amount of = -
I think that = account for the=20 AmaSeis trace showing only the top part of an = earthquake.

Hi=20 Ted,

       The input resistors = are two=20 200 K in series. The offset line is 100 K to the centre point. If any = of them=20 are damaged, it should not be difficult to replace them. = Alternatively, could=20 you  unsolder the resistors on CH4 and replace the ones on CH1? = The=20 resistor values are printed on them eg=20 2003.
       I get about -0.59 V on = the=20 offset line and about 90 mV on the input. I suspect that this is = because the=20 ADC is not in operating mode. The offset line should be -5V for +/-10V = input.=20 Check the voltage on the offset line while the channel is switched=20 on?


However Channel, 2,3,4 all seem to work showing both = positive=20 and negative movement "In DataQ Software Only", in this software = Channel 1,=20 only shows positive trace movement, and, no negative.

       You=20 could get this with failed resistors. Is the range 5V or 10V? I = suspect that=20 the ADC may have been 'modified' for a single polarity 5V signal? Can = the=20 friend who gave it to you provide any information?

When I connected my Sensor to Channel 2,3 or 4 Using=20 DataQ,  I was thinking it would then work in AmaSeis, but it = does=20 not.  It looks as if AmaSeis will not read any Channel except = Channel=20 1. Even though in DataQ Channel 2,3,4 all seem to work fine.  = If I=20 connect the sensor to Channel 3,  AmaSeis shows a trace, but = the trace=20 does not move in either direction if I stimulate the sensor.  = This is=20 true for Channel, 2,3,4.  Only Channel 1, moves the trace in=20 AmaSeis.
I think you can change the com port, in AmaSeis, = but is there=20 anywhere you can or need to change for Channel = selection?
In DataQ I = closed all the=20 Channels except Ch. 3 and saved before closing.  So If I were = just=20 using DataQ software, I would be operational.

       Amaseis = normally uses=20 CH1 only. However there are two setup files Amaseis.ini and AS1.ini. = It may be=20 possible to set a different channel by editing and then saving the = file, but I=20 am not sure. I know that you get your different sample rates this way. = If you=20 use a Dataq and Amaseis without editing the ini file, you just get 6=20 SPS.

       This information is = taken=20 from an old 8 bit DI-194 board, which I suspect that you=20 have.

      =20 Regards,

       Chris = Chapman=20

[ Top ] [ Back ] [ Home Page ]