
                        TLOG

is a simple DOS program to read a DALLAS DS1820 temperature
sensor if it is connected to the parallel port of the PC.

Wiring is simple, see attached tlog.gif


DS1820 Pins                   Parallel Printer Port Pins

1------------------------------------25
2------------------------------------1
3------------------------------------6


PIN 3 of the DS1820 connects to PIN 6 of the Printer Port. If
PIN 6 is already in use, you can use either PIN
2,3,4,5,6,7,8,9 of the PC Printer Port, they are all made HI
in the program and so can source the required 5 Volts for the
DS1820.

Requirements:

TLOG was compiled as a 16bit DOS application, requiring DOS 3.0
or above.  The PC does not have to be state of the art, any old
pc/laptop AT and above is okay, even a 20 MHz '286' 15 year old
AT can easily meet spec.  TLOG can make that old "junk" PC
suddenly have a purpose in life!

As a DIY hobby project it should only take a few minutes to put
together. After obtaining a DS1820, just wire the three
terminals via a cable to a DB25 parallel printer connector as
per the above drawing.

The program should not be run from a W9x/ME DOS window because
the program auto calibrates its timing based on the CPU clock
speed. This process is "ruined" by the W9x/ME operating system
time sharing the CPU. To use the program from W9x, you must
click on "Start" and "Shut Down" to "restart in MSDOS Mode".

Here are the Menu options of TLOG
----------------------------------------------------------------------------
             TLOG - Prototype DS1820 Temperature Monitor          Ver x.x


     Logging Data is saved to TLOG.CSV to allow direct input to EXCEL


1 - Printer Port Testing Function

2 - Raw data from DS1820 sensor, continuous sampling, NO logging

3 - Log Temperature (Centigrade) every second
4 - Log Temperature (Centigrade) every minute

5 - Log Temperature (Fahrenheit) every second
6 - Log Temperature (Fahrenheit) every minute


ENTER number for function required or ESC key to quit.
----------------------------------------------------------------------------



A screen shot of Option 2



----------------------------------------------------------------------------
                   DS1820 Raw Data Monitor                  ESC key for menu

Scratchpad Values (in Hexadecimal)

Byte 0 = 2A   LSB Temperature
Byte 1 =  0   MSB Temperature
Byte 2 = 4B   Th Register
Byte 3 = 46   Tl Register
Byte 4 = FF   Reserved
Byte 5 = FF   Reserved
Byte 6 =  D   Count Remain
Byte 7 = 10   Count per degree C
Byte 8 = D1   CRC (Cyclic Redundancy Check)

Samples = 33027     CRC Errors = 0

    MIN Temperature =  20.31 C  =  68.56 F
    AVG Temperature =  21.37 C  =  70.46 F
    MAX Temperature =  23.19 C  =  73.74 F

Current Temperature =  20.94 C  =  69.69 F
----------------------------------------------------------------------------


Run the TLOG.EXE and see if it works!


Links:

TLOG Homepage:
http://www.geocities.com/kiwi_36_nz/tlog/tlog.htm

DALLAS DS1820 Data Page
http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2815




DISCLAIMER (Oh to keep things tidy):
------------------------------------

GEOFF HITCHCOX DISCLAIMS ALL WARRANTIES, EXPRESSED OR IMPLIED,
INCLUDING BUT NOT LIMITED TO, ANY IMPLIED WARRANTY OF
MERCHANTABILITY OR SUITABILITY FOR A PARTICULAR PURPOSE.

Specifically, the author makes no representation or warranty
that the software is suitable for any particular purpose.

No claim for or right to recover any other damages, including
but not limited to, loss of profit, data, or use of the
software, or special, incidental, or consequential damages or
other similar claims can be made. In no event will the author's
liability for any damages to you or any other party ever exceed
the registration fee paid (US ZERO DOLLARS) to use the software,
regardless of any form of the claim.

Regards,  Geoff Hitchcox

http://www.geocities.com/kiwi_36_nz/

36 Tomrich Street
Christchurch
New Zealand
South Pacific.

 Latitude:  43.5197 degrees SOUTH
Longitude: 172.7022 degrees EAST

Please note: This freeware is not to be bundled with any
commercial application!

---------------End of README.TXT-----------------
