Dwyer Instruments PT500 User manual

Model PT500 Digital Pocket Thermometer
BULLETIN E-90-PT
Specifications - Installation and Operating Instructions
DWYER INSTRUMENTS, INC.
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46361 U.S.A.
Phone [phone] www.dwyer-inst.com
Fax [phone] e-mail: [e-mail]
Lit-by-Fax: [phone]
GENERAL
The PT500 Digital Thermometer is designed to meet spe-
cific needs in the food service, industrial, HVAC, labora-
tory, and scientific markets. The unit offers dual scale tem-
perature measurement in a range from -58 to 500°F (-50
to 260°C), maximum/minimum memory, two-speed dis-
play update, and field recalibration adjustment. The PT500
thermometer can be set for constant “on” state, auto-off
(after 6 to 7 minutes), or instant “off”. Use the pocket
case/clip assembly to carry the unit or as a holder when
measuring hot substances.
OPERATION
See Figure 1.
“ON” Button
Press once and release immediately. The instrument will
come on in 1 to 2 seconds. The thermometer is in the
10-second display-update frequency which conserves
battery life.
Press and hold down for 1-second displays. This is use-
ful for observing rapid temperature changes but is not
appropriate when thermometer must be removed from a
substance or an area and read before ambient tempera-
ture can effect the display. Instrument will return to 10-
second update mode when button is released.
Two-stage “OFF” Button
Leave the thermometer in the “ON” mode for long term
measurements.
Press “OFF” button once for short term measurements,
“A” will appear on LCD indicator read-out. The unit will
turn off automatically in 6 to 7 minutes.
Press “OFF” twice to turn thermometer off manually.
MAX/MIN Memory Button
Press once to switch from ambient temperature to
“Maximum Memory” reading (“MA” LCD indicator read-
out)
Press a second time to switch from “Maximum Memory”
to “Minimum Memory” reading (“MI” is displayed).
PHYSICAL DATA
Temperature Range: -58 to 500°F (-50 to 260°C), °F or °C
selectable.
Resolution: 0.1°F (0.1°C).
Accuracy: ±2°F (±1°C) from 32 to 140°F (0 to 60°C); ±5°F
(±2.7°C) below 32°F (0°C) and ±2% of reading above 140°F
(60°C).
Display: 32digit, 0.3″H.
Display Update: 1 second or 10 seconds, selectable.
Power: 1.5 Volt LR44 watch/camera battery.
Battery Life: Approximately one year.
Construction: Stainless steel pointed stem, and ABS plastic
case.
FIGURE 1
Or press twice to go directly from ambient temperature
to “ Minimum Memory” mode.
The MAX/MIN readings remain in memory until the
memory is reset. To reset maximum or minimum memo-
ry, hold down the “ON” button for more than one second
while the unit is in that memory mode.
NOTE: MAXIMUM and MINIMUM must be reset sepa-
rately.
Press “MAX/MIN” button a third time to return to ambi-
ent temperature reading.
CPU Microprocessor Reset Port
If improper display is indicated (due to changing the

battery or other power interruption) microprocessor may
be reset by pressing the CPU reset with the end of an
open paper clip. See Figure 2.
Pocket Case/Holder Assembly
The pocket case/holder assembly is used as both a con-
venient method of carrying the thermometer and as a
handle. By inserting the thermometer stem through the
ring at the top of the metal pocket clip, your hands are
protected when measuring hot or problematic sub-
stances. See Figure 4.
MAINTENANCE
No routine maintenance is required on the PT500 Digital
Pocket Thermometer. Please contact Dwyer
Instruments, Inc. before returning unit for repair to
review information relative to your application and obtain
a return authorization number. When returning a product
to the factory, carefully package and ship freight pre-
paid. Be sure to include a complete description of the
application and problem and identify any hazardous
material used with the product.
©Copyright 1998 Dwyer Instruments, Inc. Printed in U.S.A. 8/98 FR R1-443053-00
DWYER INSTRUMENTS, INC.
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46361 U.S.A.
Phone [phone] www.dwyer-inst.com
Fax [phone] e-mail: [e-mail]
Lit-by-Fax: [phone]
FIGURE 4
FIGURE 3
FIGURE 2
Recalibration Adjustment
Two variable resistors are located under the instruction
plate. The variable resistors are to be used for small
adjustments and cannot compensate for large errors
which indicate a microprocessor or sensor problem.
See Figure 3 for variable resistor locations. VR2 is used
to calibrate from -58 to 450°F (-50 to 232°C). Use VR1 to
calibrate from 450 to 500°F (232 to 260°C). Immerse the
thermometer stem at least 1″into a well-circulated bath
along with a reliable reference thermometer of known
accuracy. Carefully adjust the correct variable resistor
with an appropriate sized screwdriver.
F/C Switch
The Fahrenheit/Celsius
scales are controlled by a
slide switch on the left
side of the instrument.
Firmly press the switch
all the way to the indicat-
ed letter to ensure proper
readings.
Battery
The small round battery
compartment cover is
located on the bottom
flat of the instrument
head. Use a coin to rotate
the cover counterclock-
wise to remove. Tapping
the instrument on the
instruction plate should
cause the battery to fall
out.
Replace the battery with
the same type 1.5V
watch/camera battery
type LR44 or equivalent.
Be sure to replace the O-
ring to help prevent liq-
uids from entering the
compartment.
The CPU port may need
to be reset to restart the
unit after power interrup-
tion.