parr 6775 Instruction Manual

545M
6775/6775 A
Digital Thermometer
Operating Instruction Manual

Digital Thermometer
Parr Instrument Company
2
Table of Contents
Preface
Scope — 3
Explanation of Symbols — 3
Safety Information — 3
Intended Usage — 3
General Specifications — 3
Electrical Ratings— 3
Environmental Conditions— 3
Electromagnetic Compatibility— 3
Provisions for Lifting and Carrying — 3
Overview
Thermistor Probe Installation — 4
Operation
Installing the A366C to Use the 6775 in Place of
a GlassThermometer in a 1341 — 5
Serial Interface (6775A) — 5
Data Logging (6775A) — 6
Maintenance
Battery — 7
Customer Service
Questions concerning the installation or operation of this instrument
can be answered by the Parr Customer Service Department:
1-309-762-7716 • 1-800-872-7720 • Fax: [phone]
E-mail: par[email protected] • http://www.parrinst.com
Troubleshooting
Service — 7
Appendix 1
Calculating the CorrectedTemperature Rise
for a Calorimetric Test — 8
Dickinson Formula— 8
Regnault-Pfaundler Formula— 8
Example Calculations — 9
Calculation of the Radiation Correction and
the CorrectedTemperature Rise (t) — 9
Parts List
Principal Parts and Accessories in
6775/6775A Digital Thermometer — 10
Technical Service
Contact Us — 10
Return for Repair — 10
Drawings
Internal Parts Views of 6775 Digital
Thermometer — 11
Internal Parts Views of 6775A Digital
Thermometer — 11

Digital Thermometer
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Preface
Scope
This manual contains instructions for installing and
operating the Parr 6775 DigitalThermometer with
the 1341 Plain Jacket Calorimeter. For ease of use,
the manual is divided into 8 chapters.
Overview
Operation
Maintenance
Troubleshooting
Appendix 1
Parts Lists
Drawings
Technical Service
Subsections of these chapters are identified in the
Table of Contents.
To assure successful installation and operation, the
user must study all instructions carefully before
starting to use the DigitalThermometer to obtain an
understanding of the capabilities of the equipment
and the safety precautions to be observed in the
operation.
Explanation of Symbols
I On Position
O Off Position
Safety Information
To avoid electrical shock, always:
1. Disconnect the batteries before maintenance or
servicing.
To avoid personal injury:
1. Do not use in the presence of flammable or com-
bustible materials; fire or explosion may result.
This device contains components which may
ignite such material.
2. Refer servicing to qualified personnel.
Intended Usage
If the instrument is used in a manner not specified
by Parr Instrument Company, the protection
provided by the equipment may be impaired.
General Specifications
Electrical Ratings
7.2 VDC, 14.5 mA
Environmental Conditions
This apparatus is to be used indoors,
Operating: 10 ºC to 30 ºC; maximum relative
humidity of 80% non-condensing.
Installation Category II (over voltage)
in accordance with IEC 664.
Pollution degree 2 in accordance with
IEC 664.
Altitude
Limit: 2,000 meters.
Storage: -25 ºC to 65 ºC; 10% to 85% relative
humidity.
Electromagnetic Compatibility
Immunity: In accordance with EN 61326-1:2005,
controlled EM environment.
Emission: In accordance with EN61326-1:2005,
class A equipment.
Provisions for Lifting and Carrying
Before moving the instrument, disconnect all con-
nections from the rear of the apparatus. Lift the
instrument by grabbing underneath each corner.
Periodic cleaning may be performed on the exterior
surfaces of the instrument with a lightly dampened
cloth containing mild soap solution. All power
should be disconnected when cleaning the instru-
ment. There are no user serviceable parts inside the
product other than what is specifically called out
and discussed in this manual. Advanced trouble-
shooting instructions beyond the scope of this
manual can be obtained by calling Parr Instrument
Company in order to determine which part(s) may
be replaced or serviced.
Specifications
Probe type Thermistor
Thermometer range 10-40 °C
Resolution 0.001 °C
Sampling Time 1 second
Absolute Accuracy: The thermometer accuracy is
limited by the probe interchangeability which is 0.1 °C
Differential Accuracy: Better than 0.02 °C over any
15 °C span
Repeatability: Better than 0.001 °C

Digital Thermometer
Parr Instrument Company
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Thermistor Probe Installation
Plug the connector end of the 1168E2 thermistor probe into the 1856E connector on the back panel
(see Figure 1).
Figure 1
6775 Digital Thermometer Back Panel
Note: 2 – 1936E Lithium 3.6V batteries are used in the 6775/6775A Digital Thermometer.
Overview
Parr’s digital thermometer provides digital preci-
sion and reliability for temperature measurements
in a laboratory environment.The working tempera-
ture range of the thermometer is 10 to 40 °C with
a resolution of 0.001 °C.The thermometer uses the
30-cm long Parr 1168E2 Thermistor Probe, incorpo-
rating a durable 3.18 mm (0.125”) diameter stainless
steel sheath.This measurement system is optimized
for calorimetric temperature measurements and is
especially designed to be used with the Parr 1341
Plain Jacket Calorimeter.The digital thermometer is
offered as a replacement for the Parr 1604 [19-35 °C]
and 1623 [24-30 °C] Liquid-in-GlassThermometers.
However, the thermometer is equally well suited
for other types of temperature measurement tasks
in the 10 to 40 °C range where high precision mea-
surements are required.The thermometer is bat-
tery powered using high capacity lithium batteries,
providing approximately 200 hours of operation. It
comes equipped with an easy to read two-line, 16
characters per line, liquid crystal display. In addition
to displaying temperature, the thermometer pro-
vides a free-running timer that can be used to time
stamp temperature measurements or to aid the user
in recording temperatures at regular time intervals.
The 6775A DigitalThermometer incorporates all of
the aforementioned features and offers the follow-
ing additional capabilities.
The 6775A thermometer provides for operation with
a second temperature probe.This second probe can
be used to monitor the temperature of a second
calorimeter or the calorimeter jacket temperature.
Acquiring both the calorimeter and jacket tempera-
tures can be used to facilitate rigorous calorimeter
heat leak correction calculations during long dura-
tion tests.
The 6775A thermometer comes equipped with a
serial RS-232C interface.This interface is used to
configure the thermometer for advanced operation
such as two channel operation.The interface capa-
bility is also used to permit logging temperatures
at a user specified time interval.The user interacts
with the thermometer through a simple command
line interface using any terminal emulation program
installed on a host PC.

Digital Thermometer
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Operation
Plug the probe into the receptacle.
Turn the power switch on.
The thermometer will automatically perform an ini-
tial internal electronic calibration immediately after
power is applied.
Immerse the stainless steel portion of the probe into
the liquid to be measured. In most instances, the
depth of probe immersion needs to be approximate-
ly 10 cm in order to minimize errors related to stem
conduction.
Turn the ON/OFF switch to the off position when the
thermometer is not in use to prolong the battery life.
If the 1341 Plain Jacket Calorimeter originally used
a glass thermometer then the A366CThermistor
Conversion kit will need to be installed. Contact
Parr Instrument Company or your local distributor
for details.
Installing the A366C to Use the 6775 in
Place of a Glass Thermometer in a 1341
1. Remove the 467W black plastic bushing from the
top cover of the 1341.
2. Remove the 3 screws holding the 40C thermom-
eter support plate to the top cover of the 1341.
3. Position the 347C so that the middle hole is lined
up with the thermometer hole in the cover and
the two small holes line up with the two screw
holes.
4. Re-install the 3 screws. The third screw is op-
tional as it no longer secures anything.
5. Install the 213VBAD nut and the 214VBHJ ferrule
set on the 347C. See Figure 2.
6. Slide the 1168E2 thermistor into the 213VBAD
and 214VBHJ then through the 347C.
7. Adjust the length of the thermistor extending be-
low the cover to approximately the same length
as the stirrer shaft.
8. Hand-tighten the 213VBAD nut to secure the
1168E2 thermistor.
Note: Do not over tighten the nut.
Serial Interface (6775A)
The 6775A is equipped with a serial RS-232C inter-
face.The user interacts with the thermometer using
a terminal emulation program installed on a host
PC. Parr recommends a program known as PuTTY
for this purpose.The program is freely available at
the following URL address.
http://www.putty.org
Realizing that most contemporary PCs no longer
have RS-232C serial ports, Parr includes a 2286E
USB to serial adapter and 2261E USB extension
cable to provide connectivity between the thermom-
eter and a PC. The adapter attaches directly to the
9 pin DS connector on the rear of the thermometer.
Otherwise, a so-called straight through style three
wire serial cable is used to connect the thermometer
to a legacy PC serial port.
Figure 2

Digital Thermometer
Parr Instrument Company
6
After a suitable electrical connection is established
between the thermometer and the PC, start PuTTY.
Select a serial connection type and enter the appro-
priate COM port number associated with the USB
interface.The COM port information is available us-
ing the Windows Device Manager.The transmission
speed is 9600 bps and the data frame is 8 data bits,
1 stop bit and no parity.The thermometer does not
support any type of data flow control.
Cycle power on the thermometer and the following
banner should appear in the terminal window.
ParrThermometer - $Rev: 100 $
Press the h key to display the following menu.
Pressing 1 selects single channel operation and 2
selects operation with two temperature probes.
Pressing C allows the user to adjust the LCD con-
trast. Low values result in a darker display and
higher values produce opposite results. Values near
the middle of the span (1800-1900) generally provide
the best contrast at typical ambient temperatures.
Options D and U are for factory use only and are
unsupported.
Option L sets the data log interval.This option is
discussed in greater detail in the following section.
Pressing theT key resets the free running timer.
Option S allows the user to display temperatures
in degrees Celsius or Fahrenheit. The ohms option
displays the probe resistance.This is used primarily
for diagnostic purposes.
Pressing the V key displays the thermometer firm-
ware revision.
ParrThermometer - Rev. $Rev: 100 $
1 - Single channel mode
2 -Two channel mode
C - Set contrast (Value >= 900 and <= 2800)
D - Download configuration file
U - Upload configuration file
L - Set data logging interval in sec. (0=Disabled)
H - Display command help
T - Reset timer
S - Toggle units scale (C,F,Ohms)
V - Display software version
Data Logging (6775A)
Menu option L prompts the user for a data logging
time interval in seconds. Values between10 to 60
seconds are suitable for the majority of calorimetric
applications. After setting the time interval, tempera-
ture readings are displayed in the terminal window
at the specified time interval. All readings are time
stamped and the selected temperature units are ap-
pended to each record as shown below.
Enter Log Interval in seconds (0=Off): 10
Log interval is 10
> 00:34:55,22.980,0.000,C
00:35:05,22.979,0.000,C
00:35:15,22.973,0.000,C
00:35:25,23.000,0.000,C
00:35:35,22.973,0.000,C
00:35:45,22.996,0.000,C
00:35:55,22.992,0.000,C
00:36:05,23.008,0.000,C
00:36:15,23.008,0.000,C
Individual datum in each record are separated
by commas to facilitate export of the data into a
spreadsheet program such as Excel. Right click on
the upper border of the PuTTY terminal window and
select Copy All to Clipboard. Open a text editor, such
as Notepad, and paste the contents of the clipboard.
Edit the file as required deleting everything except
the time – temperature data. Save the edited file and
then open the file using Excel.The ExcelText Import
Wizard is displayed.The file type is delimited and
the delimiter is a comma. Select Finish to display
the imported data.
PuTTY is also capable of session logging all print-
able output automatically to a log file on the PC.This
method of capturing data is recommended when
data is collected over an extended period of time.
Appendix 1 offers a discussion of two complemen-
tary methods typically used to calculate the cor-
rected temperature rise for a calorimetric test from
logged data collected at regular time intervals. Both
numerical treatments illustrated are easily adapted
and applied to calorimetric test data presented in a
spreadsheet format.

Digital Thermometer
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Maintenance
Refer to Manual 204M, Operating Instructions for
the 1341 Plain Jacket Calorimeter for calorimeter
maintenance information.
Refer to Manual 205M, Operating Instructions for
the 1108 Oxygen Combustion Vessel for bomb
maintenance information.
ATTENTION: Electrostatic Discharge (ESD)
hazards. Observe precautions for handling
electrostatic sensitive devices
There is no routine maintenance recommended for
the 6775 DigitalThermometer.
Battery
The thermometer is battery powered using high
capacity lithium batteries (2 x 1936E), providing ap-
proximately 200 hours of operation.
If the thermometer display fails to operate, it most
likely indicates the batteries are low and need to be
replaced. To replace the batteries, twist the battery
cover counterclockwise to expose the batteries.
Replace the old batteries with two new batteries.
Do NOT replace the batteries with ordinary AA style
batteries. Ordinary AA batteries will not provide suf-
ficient voltage to power the thermometer. Slide the
new batteries into the battery holder observing the
correct polarity. Replace the battery cover.
Troubleshooting
If the thermometer does not function properly for
any reason, please replace the batteries with new
ones. See the Battery section, above. Low battery
power can occasionally cause a number of apparent
operational difficulties. Replacing the batteries will
solve most difficulties.
Service
For technical assistance or service contact:
Parr Instrument Company
211 53rd Street
Moline, IL 61265
Telephone: [phone]
Toll Free: 1-800-872-7720
Fax: [phone]
E-mail: par[email protected]
www.parrinst.com

Digital Thermometer
Parr Instrument Company
8
Appendix 1
Calculating the Corrected Temperature Rise
for a CalorimetricTest
There are two generally accepted methods for cal-
culating the correction for heat gain or loss from a
non-adiabiatic oxygen bomb calorimeter.The first
method for calculating the correction is based upon
the work of Dr. H.C. Dickinson at the National Bureau
of Standards who showed that the amount of heat
leak during a test could be approximated by assum-
ing that the calorimeter is heated by its surround-
ings during the first 63 percent of the temperature
rise at a rate equal to that measured during the
5-minute preperiod.The method then assumes that
the cooling (or heating) rate during the remaining 37
percent of the rise is the same as the rate observed
during the 5-minute postperiod. For most experi-
mental work the dividing point between these two
periods is taken as that point in time, b, when the
temperature has reached six-tenths (instead of 63%)
of the total rise.This method is given by the follow-
ing formula.
Dickinson Formula
Cr= - r1(b – a) – r2(c – b)
where:
Cr= radiation correction
r1= rate of rise in temperature in the
preliminary period. If temperature is
falling, r1is negative
r2= rate of rise of temperature in the final
period. If temperature is falling, r2is
negative
ta= firing temperature
tc= fi nal temperature, being the fi rst
temperature after which the rate of
change is constant
a = time at temperature ta
b = time at temperature ta+ 0.60 (tc— ta)
c = time at temperature tc
The second technique of making such correction is
by the use of a method originally developed by the
French chemist and physicist Henri Victor Regnault
and later modified by Leopold Pfaundler otherwise
known as the Regnault-Pfaundler method.This
method assumes that starting with an initial rate
of heat exchange in the preperiod and ending with
a final rate in the postperiod that the rate of heat
exchange during the main period is proportional to
the initial and fi nal rates. That is, the rate of heat ex-
change at a point halfway through the main period
will be the mean of the initial and final rates.This
halfway point is achieved when the calorimeter tem-
perature equals the integrated mean temperature
during the main period.This method is given by the
following formula.
Regnault-Pfaundler Formula
Cr= (c – a) (k (tm- ) – r1) = (c – a) (k ( - tm) – r2)
where:
Cr= radiation correction;
k = (r1– r2) / ( – )
The above quantity is often referred to as the spe-
cific rate constant of the calorimeter.
tm = 1/n ( + (ta+ tc) / 2)
The above quantity is the integrated mean tempera-
ture during the main period.This value results from
the numerical integration of temperature values in
the main period using the trapezoidal rule.

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n =
the number of temperature read-
ings in the combustion period
after firing
=average temperature during the
preliminary period
=average temperature during the
final period
t1, t2, . . .
tn
=
successive temperatures recorded
during the combustion period
after firing at equal time intervals
(e.g. one minute)
=the sum of t1, t2, t3… tc-1
The remaining symbols are the same as defined
in the Dickinson formula. In general, the results
obtained by the two methods are in practical agree-
ment.
The corrected temperature rise is given by the fol-
lowing formula: t = tc– ta+ Cr
Example Calculations
Observed CalorimeterTemperature Readings
Time / minutes Temperature / C
0 (start) 22.439 tstart
1 22.447
2 22.454
3 22.462
4 22.469
5 (a) 22.477 ta
6 (b) 23.896
7 24.555
824.714
9 24.770
10 24.792
11 24.802
12 24.806
13 24.809
14 24.812
15 (c) 24.814 tc
16 24.816
17 24.818
18 24.820
19 24.821
20 (end) 24.823 tend
Calculation of the Radiation Correction and the Corrected Temperature Rise (t)
r1= (ta– tstart) / (a – start) = (22.477 – 22.439) / 5 = 0.0076
r2= (tend – tc) / (end – c) = (24.823 – 24.814) / 5 = 0.002
= (ta+ tstart) / 2 = (22.477 + 22.439) / 2 = 22.458
= (tend + tc) / 2 = (24.823+ 24.814) / 2 = 24.818
k = (r1– r2) / ( - ) = 0.0024
tm = 1/n ( + (ta+ tc) / 2) = 1/10 (221.956 + 23.646) = 24.560
Cr(Dickinson) = - r1(b – a) – r2(c – b) = - 0.0076 (1) – 0.002 (9) = - 0.026
Cr(Regnault-Pfaundler) = (c – a) (k (tm- ) – r1)= (15 – 5) ((0.0024) (24.560 – 22.458) – 0.0076) = - 0.026
tDickinson = tc– ta+ Cr = (24.814 – 22.477) – 0.026 = 2.311
tRegnault-Pfaundler = tc– ta+ Cr= (24.814 – 22.477) – 0.026 = 2.311

Digital Thermometer
Parr Instrument Company
10
Parts List
Principal Parts and Accessories in 6775/6775A Digital Thermometer
Part Number Description Quantity
1936E Battery, Lithium 3.6V 2
2026E Holder, Battery (2)AA 1
361C Bezel, Display; Black 1
362C Clip, Bezel Retainer 2
1653E Ferrite, Bisected Sleeve .350 1
2027E Switch, Rocker 1
1168E2 Thermistor Probe 1
A1862E Thermistor Harness 6775 1 / 2*
2286E* Cable, RS232 to USB (6775A) 1
2261E* Cable, USB Extension (6775A) 1
* 6775A only
Technical Service
Contact Us
Should you need assistance in the operation or ser-
vice of your instrument, please contact the Technical
Service Department.
Telephone: [phone]
Toll Free: 1-800-872-7720
Fax: [phone]
E-mail: par[email protected]
Any correspondence must include the following
basic information:
1. The model and serial # of the instrument.
2. Date purchased.
When calling by phone, it is helpful if the person is
close to the instrument in order to implement any
changes recommended by theTechnical Service
Department.
Return for Repair
To return the instrument for repair, please call
theTechnical Service Department for shipping
instructions and a RETURN AUTHORIZATION
NUMBER. This number must be clearly shown
on the outside of the shipping carton in order to
expedite the repair process.
Ship repair to:
Parr Instrument Company
Attn: Service Department, RMA# XXXX
211- 53rd Street
Moline, Illinois 61265