DTH51-MAN
P. 5
Low Battery Indication
The low battery indication appears when battery power runs low. Low
batteries will adversely affect the accuracy of your readings. When the
icon appears (Fig 8):
1. Remove the battery door.
2. Remove and replace all four “AA” batteries.
3. Replace the battery door.
Calibration
CAUTION!
DO NOT
p e rform this pro c e d u re unless you have calibration salts available.
Annual calibration is recommended for this instrument. To calibrate,
have 33% and 75% calibration salts ready, ensure that all materials and
the ambient temperature are as close as possible to 73˚F (23˚C) and:
1. Turn off the meter and insert the sensor-set into a 33% salt bottle.
2. Press and hold in the “ “ and “ “ at the same time.
3. Press “ “ to power on the instrument.
4. 32.8% will be flashing on the bottom line of the DTH51.
5. Leave the instrument in the 33% calibration-salt solution
for 30 minutes.
6. After 30 minutes the 32.8% will stop flashing and become steady.
7. Move the sensor-set into the 75% calibration-salt solution.
8. Press the “ “ push-button again.
9. 75.2% will be flashing on the screen.
10. After 30 more minutes, press the “ “ push-button for the
final time.
The calibration process is complete and stored in memory. Turn the
meter off and back on to reboot.
NOTE:
You can exit (abort) calibration without storing new references
by pressing the “ “ key for more than 2 seconds (turning the
meter off) if performed prior to step 6.
Auto Power Off is disabled during the calibration process.
RS232 Communications
Software (not provided)
This device can communicate with computers using Windows integrated
Hyper Terminal software.
Communications set-up
RS232 Interface (3.0V level)
A. 9600 bps, 8 data bits, no parity
B. Format: DTH51 transmits one ASCII word per second
while meter Txxx.xC: Txx.xC: Hxx.x%: Txx.xCLRC
CRLF
Where:
The 1st value is IR temp.
The 2nd value is Air temp.
The 3rd value is Humidity
The 4th value is Wet Bulb
The 5th value is Dew Point
The x in the data string above indicates one of {0|1|2| |9|-}
C. Format for error value:
E01No value
E02 Overflow
E03 Underflow
The unit for error code is n. Ex.
If IR is disabled, then tx
TE01n:T23.5C:H45.3%:T14.9C:T12.3CLRC
CRLF
Error value
Low Battery Icon
(Fig 8)
