Isotech milliK Operating instructions

User Maintenance Manual/Handbook
Issue 3.02
Software version 3.0.0+
Firmware version 3.0.34+
Isothermal Technology Limited, Pine Grove, Southport, PR9 9AG, England
Tel: [phone] Fax: [phone] Internet: www.isotech.co.uk
E-mail: [email protected]
The company is always willing to give technical advice and assistance where appropriate. Equally, because of the
programme of continual development and improvement we reserve the right to amend or alter characteristics and design
without prior notice. This publication is for information only.

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Contents
1Introduction .......................................................................................................................6
1.1 Unpacking....................................................................................................................6
1.2 Safety ...........................................................................................................................6
2Getting Started...................................................................................................................9
2.1 A Quick Tour of Your milliK .....................................................................................11
2.2 Driving your milliK.....................................................................................................13
2.2.1 The ‘Graph’ Window .........................................................................................14
2.2.2 The ‘Numeric’ Window .....................................................................................14
2.2.3 The ‘Settings’ Window.......................................................................................15
2.2.4 The ‘Instrument’ Window..................................................................................17
2.3 Battery Operation .....................................................................................................18
3Detailed Description by Function....................................................................................19
3.1 Using a PRT/SPRT with milliK ...................................................................................19
3.1.1 Configuring milliK to measure a PRT/SPRT .......................................................20
3.1.2 Determining Self-Heating of a PRT/SPRT..........................................................22
3.1.3 Using 3 or 4 Wire Measurement .......................................................................22
3.2 Using a Thermistor with milliK..................................................................................24
3.2.1 Configuring milliK to Measure Temperature with a Thermistor.......................25
3.3 Using a Thermocouple with milliK............................................................................26
3.3.1 Using Internal Reference Junction Compensation .............................................27
3.3.2 Using External Reference Junction Compensation ............................................27
3.3.3 Using an Ice-Point for the Reference Junction...................................................28
3.3.4 Configuring milliK to Measure a Thermocouple................................................29
3.4 Using a 4-20mA Transmitter with milliK...................................................................31
3.4.1 Configuring milliK to Measure a 4-20mA Transmitter ......................................32
3.5 Measuring the Difference Between Two Channels ..................................................33
3.6 Changing Graph Scales ..............................................................................................33
3.7 Using Rolling Statistics ...............................................................................................34
3.8 Logging Results to a File ............................................................................................35
3.8.1 Transferring Logged Data to a PC .....................................................................37
3.8.2 File Format for Logged Data..............................................................................38
3.8.3 Clearing Logged Data from Internal Memory....................................................38
3.9 Using the Thermometer Database ...........................................................................39
3.9.1 Creating a New Thermometer Entry................................................................39
3.9.2 Using a PRT with IEC60751 (2008) Conversion ...............................................41
3.9.3 Using a PRT with Callendar Van Dusen Conversion .........................................42
3.9.4 Using a PRT with ITS90 Conversion..................................................................43
3.9.5 Using a Thermocouple with Calibration Coefficients / Data Pairs ....................44
3.9.6 Using a Thermistor with the Steinhart-Hart Polynomial ...................................45
3.9.7 Using a Thermistor with Polynomial Temperature Conversion .......................46
3.9.8 Using a 4-20mA Transmitter with Linear Conversion.......................................47
3.10 Updating the Software...........................................................................................48
3.11 Using and Changing Passwords .............................................................................48
3.11.1 Recovering a Lost Password ..............................................................................49
3.12 Controlling Temperature Sources with milliK.......................................................50

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3.12.1 Creating a Temperature Profile.........................................................................52
4Connecting Thermometers to milliK...............................................................................54
4.1 Connecting PRTs/SPRTs to milliK .............................................................................54
4.2 Connecting Thermistors to milliK .............................................................................55
4.3 Connecting Thermocouples to milliK .......................................................................56
4.4 Connecting 4-20mA Transmitters to milliK ..............................................................57
5Calibration........................................................................................................................58
5.1 Standards Required for Calibration ...........................................................................59
5.1.1 Making a 4-Terminal Short-Circuit ....................................................................59
5.1.2 Making a 0mV Source in a Thermocouple Connector ......................................60
5.2 Checking the Calibration...........................................................................................60
5.2.1 PRT/SPRT Resistance Range ..............................................................................61
5.2.2 Thermistor Resistance Range (500k) –Span Check.......................................63
5.2.3 Thermocouple Voltage Range –Zero Check ....................................................63
5.2.4 Thermocouple Voltage Range –Span Check.....................................................64
5.2.5 4-20mA Transmitter Range –Zero and Span Check ........................................65
5.2.6 Reference Junction Compensation Accuracy.....................................................66
5.3 Adjusting the Calibration...........................................................................................67
5.3.1 Starting the Calibration Adjustment Feature .....................................................68
5.3.2 Adjusting SPRT (115Ω) Resistance Range..........................................................68
5.3.3 Adjusting PRT (460Ω) Resistance Range............................................................69
5.3.4 Adjusting Thermistor (500kΩ) Resistance Range ..............................................70
5.3.5 Adjusting Zero Voltage Offsets..........................................................................70
5.3.6 Adjusting Voltage Gain .......................................................................................70
5.3.7 Adjusting 4-20mA Transmitter Range................................................................71
5.3.8 Adjusting the RJC Sensor Calibration.................................................................72
5.4 Exporting Calibration information.............................................................................73
6Maintenance and Cleaning ...............................................................................................74
7Interfacing to milliK ..........................................................................................................75
7.1 Isotech Software........................................................................................................75
7.2 RS232 Interface .........................................................................................................75
7.2.1 Establishing an RS232 Connection .....................................................................76
7.3 Ethernet Interface .....................................................................................................79
7.3.1 Establishing an Ethernet Connection .................................................................79
7.3.1 Using SCPI Commands with the Ethernet Connection.....................................81
7.3.2 Using Remote Desktop Access..........................................................................82
8SCPI Command Set .........................................................................................................84
8.1 Command Terminators.............................................................................................84
8.2 SCPI Command Structure.........................................................................................84
8.3 SCPI Numeric Suffices...............................................................................................85
8.4 Parameters ................................................................................................................85
8.5 Units ..........................................................................................................................86
8.6 Making Measurements Using SCPI Commands ........................................................86
8.6.1 Measuring Resistance using SCPI Commands....................................................87
8.6.2 Measuring Voltage (with optional RJC) using SCPI Commands.........................87
8.6.3 Measuring Current using SCPI Commands .......................................................89
8.6.4 Measuring Temperature using SCPI Commands...............................................89
8.6.5 SCPI Commands ................................................................................................95

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8.6.6 Command: *IDN? ..............................................................................................97
8.6.7 Command [MILLik:]REMote..............................................................................98
8.6.8 Command [MILLik:]LOCal ................................................................................98
8.6.9 Command SENSe:FUNCtion[:ON]...................................................................99
8.6.10 Command SENSe:FUNCtion[:ON]? .................................................................99
8.6.11 Command SENSe:CHANnel .............................................................................99
8.6.12 Command SENSe:CHANnel? ..........................................................................100
8.6.13 Command SENSe[:RESistance]:RANGe[:UPPer]............................................100
8.6.14 Command SENSe[:RESistance:]RANGe[:UPPer]?...........................................100
8.6.15 Command SENSe:RESistance:WIRes...............................................................101
8.6.16 Command SENSe:RESistance:WIRes? .............................................................101
8.6.17 Command SENSe:CURRent ............................................................................101
8.6.18 Command SENSe:CURRent?...........................................................................102
8.6.19 Command SENSe:PROBe................................................................................102
8.6.20 Command SENSe:PROBe? ..............................................................................103
8.6.21 Command SENSe:UNITs.................................................................................103
8.6.22 Command SENSe:UNITs? ...............................................................................103
8.6.23 Command SENSe:RJC .....................................................................................103
8.6.24 Command SENSe:RJC? ....................................................................................104
8.6.25 Command INITiate[:IMMediate][:ALL] ...........................................................104
8.6.26 Command FETCh[:SCALar]?...........................................................................104
8.6.27 Command READ[:SCALar]? ............................................................................104
8.6.28 Command MEASure[:SCALar]:TEMPerature<channel#>? ..........................105
8.6.29 Command MEASure[:SCALar]:VOLTage[:DC]<channel#>? .......................106
8.6.30 Command MEASure[:SCALar]:RESistance<channel#> ................................107
8.6.31 Command MEASure[:SCALar]:CURRent?.......................................................107
8.6.32 Command MEASure[:SCALar]:RJC? ................................................................107
8.6.33 Command PROBe:UNLock.............................................................................108
8.6.34 Command PROBe:LOCK ................................................................................108
8.6.35 Command PROBe:COUNt? ............................................................................108
8.6.36 Command PROBe:NAMe<probe#> ............................................................108
8.6.37 Command PROBe:NAMe<probe#>? ...........................................................108
8.6.38 Command PROBe:TYPe<probe#> ..............................................................109
8.6.39 Command PROBe:TYPe<probe#>?.............................................................109
8.6.40 Command PROBe:MANufacturer<probe#> ...............................................109
8.6.41 Command PROBe:MANufacturer<probe#>? ..............................................109
8.6.42 Command PROBe:MODel<probe#>...........................................................110
8.6.43 Command PROBe:MODel<probe#>?..........................................................110
8.6.44 Command PROBe:SERial<probe#> .............................................................110
8.6.45 Command PROBe:SERial<probe#>? ............................................................110
8.6.46 Command PROBe:DATe<probe#> .............................................................111
8.6.47 Command PROBe:DATe<probe#>?............................................................111
8.6.48 Command PROBe:MINimum<probe#>.......................................................111
8.6.49 Command PROBe:MINimum<probe#>? .....................................................111
8.6.50 Command PROBe:MAXimum<probe#> .....................................................112
8.6.51 Command PROBe:MAXimum<probe#>? ....................................................112
8.6.52 Command PROBe:WIRes<probe#>.............................................................112
8.6.53 Command PROBe:WIRes<probe#>? ...........................................................112

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8.6.54 Command PROBe:CONVersion<probe#>..................................................113
8.6.55 Command PROBe:CONVersion<probe#>? ................................................114
8.6.56 Command PROBe:COEFficient<probe#> ...................................................114
8.6.57 Command PROBe:COEFficient<probe#>?..................................................115
8.6.58 Command PROBe:CVD:FORM.......................................................................115
8.6.59 Command PROBe:CVD:FORM? .....................................................................116
8.6.60 Command PROBe:ITS90:FORM<probe#> ..................................................116
8.6.61 Command PROBe:ITS90:FORM<probe#>?.................................................116
8.6.62 Command PROBe:CREate ..............................................................................117
8.6.63 Command PROBe:DELete<probe#>...........................................................117
8.6.64 Command PROBe:FIND? ................................................................................117
8.6.65 Command CALibrate:UNLock........................................................................117
8.6.66 Command CALibrate:LOCK ...........................................................................118
8.6.67 Command CALibrate:RESistance:GAIN ..........................................................118
8.6.68 Command CALibrate:RESistance:GAIN?.........................................................118
8.6.69 Command CALibrate:VOLTage:OFFSet<channel#>...................................119
8.6.70 Command CALibrate:VOLTage:OFFset<channel>? .....................................119
8.6.71 Command CALibrate:VOLTage:GAIN............................................................119
8.6.72 Command CALibrate:VOLTage:GAIN?...........................................................120
8.6.73 Command CALibrate:CURRent:GAIN............................................................120
8.6.74 Command CALibrate:CURRent:GAIN?...........................................................120
8.6.75 Command CALibrate:RJC:OFFSet ..................................................................121
8.6.76 Command CALibrate:RJC:OFFSet? .................................................................121
8.6.77 Command CALibrate:IDENtification...............................................................121
8.6.78 Command CALibrate:IDENtification? .............................................................122
8.6.79 Command CALibrate:IDENtification:LAST?....................................................122
8.6.80 Command CALibrate:PASSword.....................................................................122
8.6.81 Command CALibrate:VALid?...........................................................................122
9Specification ...................................................................................................................123
10 Approvals .......................................................................................................................126
10.1 CE Declaration ....................................................................................................126
10.2 FCC Statement ....................................................................................................126
10.3 Standards Applied ................................................................................................127
11 Revision History .............................................................................................................127

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1Introduction
The milliK precision thermometer provides a complete measurement and control interface
for users wishing to make high accuracy temperature measurements or calibrate
thermometers. It supports a wide range of thermometer types including 25ΩSPRTs, 100Ω
PRTs, thermistors, thermocouples and 4-20mA transmitters (self-powered and loop-
powered) and can control Isotech temperature sources, sequencing through a programmable
list of temperature set points whilst logging data to internal memory or a USB drive.
The milliK sets new measurement standards in its class (<±5ppm for SPRTs/PRTs, <±2µV
for thermocouples, <±50ppm for thermistors and <±0.01% for current transmitters). The
Windows™ CE operating system provides a simple and intuitive user interface and with a
wide range of interfaces (USB, RS232, ethernet) allows the user to access the comprehensive
features of the milliK. A USB keyboard and mouse can be plugged into the milliK to make
control and data entry with the milliK as simple as using a laptop PC.
1.1 Unpacking
Your product should comprise the following items:
milliK Precision Thermometer
power supply with interchangeable plug heads
two Lemo 6-pin connectors
null modem RS232 cable
this user manual
If any item is missing or damaged, please report this immediately to your supplier. If possible,
we recommend that you retain the packaging material in case you need to return the
instrument for calibration or service.
1.2 Safety
The milliK is a precision instrument, designed for use in a laboratory or light industrial
environment. It complies with the requirements of safety standard EN61010-1 (2001) and is
therefore safe to use in laboratory or light industrial environments. It is not intended for use
outdoors or in extreme environments (refer to specification in Section 9).

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!
The milliK is likely to be connected to thermometer sensors in use and the user should take
care to ensure that the complete system is safe. For example, metal sheathed thermometers
may be connected to the milliK and then placed in a furnace powered from a 230V electrical
supply. Single fault conditions in such a furnace could lead to the thermometer wires and the
front terminals of the milliK, to which they are connected, becoming electrically live and
therefore a hazard to the user. Suitable precautions should be taken, such as using an
isolating transformer in the supply to such a furnace. If you require further advice on safety
issues, please contact Isothermal Technology or one of our appointed distributors - we have
extensive experience of thermometry and can provide advice and equipment to help you.
Retain these instructions. Use only as specified in these operating instructions or the intrinsic
protection may be impaired.
Please observe the following safety precautions:
Do not use your milliK if it is damaged
Only connect the power supply to an electrical supply that conforms to the
specification given on its rating plate
This equipment is for indoor use within an ambient temperature range of 0°C to 40°C
with maximum relative humidity of 95%
This equipment is for use in moderate climates only. NEVER use the equipment in
damp or wet conditions
Avoid excessive heat, humidity, dust & vibration
Do not place liquid filled containers on the equipment
Do not use where the equipment (or any associated accessories) may be subjected to
dripping or splashing liquids
Ensure all cables and wires are routed safely to avoid tripping: also, to avoid sharp
bends and pinches
Clean only with a damp cloth. Do not wet or allow moisture to penetrate the
equipment. Do not use solvents; see section 6 for details of cleaning procedure
The product should be subjected to regular in-service inspections as required by local
regulations; a yearly interval is suggested
Do not apply earth test currents to any terminals nor to the shrouds of the USB,
RS232, or ethernet connectors
The product is designed to comply with EN 61010-1 and can be flash tested. It is
fitted with radio frequency interference suppressors. Therefore, it is recommended
that only a D.C. test be performed. Performing flash tests repeatedly can damage
insulation
This equipment contains no user-serviceable parts. Refer all repairs to qualified
service personnel. Contact Isothermal Technology or one of our appointed
distributors for details of approved service outlets
The power supply has been approved to the following safety standards:

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UL60950-1, 2nd Edition: 2007-03-27
CSA C22.2 No. 60950-1-07, 2nd Edition: 2007-03
EN 60950-1: 2006 including A11
BS EN60950-1: 2006
AS/NZS60950-1: 2003 including amendments 1, 2 and 3

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2Getting Started
The power supply operates from any standard AC electrical supply (90-264V RMS at 47-
63Hz), so unless your supply is unusual you can simply connect the power supply to a
suitable electrical outlet.
The power supply is fitted with a standard BS 1363 plug head but is provided with alternative
heads that cover the majority of electrical sockets used worldwide. If you need to connect to
an outlet socket that is not supported by the plug heads provided, you should source a
suitable adaptor to suit one of these connector heads. The plug head can easily be changed
by pressing the head release button on the connector head and sliding it off of the power
supply body:

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Plug the DC connector from the power supply into the “DC Power” socket on the rear of
the milliK. Press the on/off button on the front panel to turn on your milliK. The milliK will
load the operating system and software (25s) and then restore itself to the settings used
when it was de-powered. This manual provides comprehensive details on using your milliK.
In addition video tutorials are available on the Isotech website (see video tab at
www.isotech.co.uk/precision-thermometers/instruments/instruments/millik-precision-
thermometer).
Head Release Button
Do NOT insert plug head alone into socket

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2.1 A Quick Tour of Your milliK
On the front of your milliK you will find two sets of connectors (Lemo 6-pin circular
connectors for SPRTs/PRTs/thermistors and miniature thermocouple connectors) for
channels 1 and 2. On the rear of your milliK you will find the 4mm sockets for channel 3
(used exclusively for 4-20mA transmitters).
Colour
LCD
Up/Down/
Left/Right/
Enter keys
Context
Sensitive
Function
Keys
Channel 1
Lemo
Connector
(
Channel 1
Miniature
Thermocouple
Connector
Channel 2
Lemo
Connector
Channel 2
Miniature
Thermocouple
Connector
On/Off
Button
Tilt
Feet

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The milliK is controlled using the (left/right/up/down/enter) key cluster and the 4
function keys located below the display. The keys are used to navigate between
items on the screen and the key is used to select or toggle the highlighted item. The
function keys select the context sensitive function displayed above each key. The milliK will
display soft keyboards when required so that all features of the milliK can be accessed using
these keys. You can also connect a keyboard and/or mouse to the USB port (rear panel) and
use these to control the milliK. The function keys below the display are mapped to keys F1-
F4 on the keyboard so that you can control the milliK completely using a USB keyboard.
The milliK is also equipped with two RS232 ports (these are completely interchangeable), a
USB 2.0 host port and ethernet port (10/100MBit), which are available on the rear panel.
The milliK is primarily for use as a bench-top laboratory standard but can also be powered
from 4 x AA cells (Ni-MH, Alkaline or Lithium) if a suitable electrical supply is not available
(typical rechargeable Ni-MH cells provide > 4 hours operating life). The battery
compartment is located on the rear panel.
Battery
Compartment
DC
Power
Input
RJ45
Ethernet
Connector
USB Host
Connector
RS232
Connector
(COM1)
RS232
Connector
(COM2)
4mm
Sockets for
Channel3
(4-20mA)

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2.2 Driving your milliK
When the milliK is turned on, the opening window appears showing the configuration:
Press the right-hand function key below Start to proceed (or connect a USB keyboard or
mouse and press F4 or click Start). The milliK software will then start and you will see the
main Windows:
There are four main windows, which can be selected using the function keys below the
display. The software always starts with the Graph window selected as shown above.
We will now provide a description of each window. If you wish to perform a particular
function (for example changing the time/date) then you can find help on this by locating it in
the table of contents at the start of this manual and going straight to the relevant section.

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2.2.1 The ‘Graph’ Window
In the Graph window you can view a single channel (or the difference between any channel
and Channel 1) in graphical and numerical form. Functions available from within this window
are:
Select which channel (or the difference between which channel and channel 1) to
view
Clear the graph
Set the scales for the graph (automatic scaling available for vertical axis)
Start/stop logging of data to internal or external (USB drive) memory
Use the  keys to select from the buttons displayed at the top of the screen and press the
key to activate that function (for example, to clear the statistics). To change which channel
is displayed (or to select a difference) use the  keys to select the right-hand button and
either use the  keys to sequence through the channels or press the key to open a
window containing a list of all the available channels. Only channels that are enabled (in the
‘Settings’ window) appear, so if only one channel is enabled this button has no effect.
2.2.2 The ‘Numeric’ Window
In the Numeric window you can view enabled channels in numeric form, together with
their mean and standard deviations. Channels that are not enabled in the Settings window
do not appear. You can choose whether to view a single channel with a large font or all the
channels with a smaller font using the Single Channel / All Channels button. If you choose
to view a single channel then the base units for the thermometer will be displayed at the
same time:

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Functions available from within this window are:
Select which channel (or the difference between which channel and channel 1) to
view
Select whether to display a single channel or all channels
Clear the rolling statistics and reset the statistics counter
Start/stop logging of data to internal or external (USB drive) memory
Use the keys to select from the buttons displayed at the top of the screen and press
the key to activate that function (for example, to clear the statistics).
2.2.3 The ‘Settings’ Window
In the ‘Settings’ window you can change the settings for each measurement channel.
Use the keys to select the setting you wish to change and then use the keys to
change it to the required value. If a channel is not being used, it is best to change its ‘Status’
to “Disabled” as this will then make the measurement time available to other enabled
channels, which will speed up these measurements. The ‘Type’ field is for information

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purposes only and cannot be changed. Pressing the key when the ‘Thermometer’ setting is
selected opens a window with a list of all thermometers in the milliK’s database:
Use the keys to highlight the required thermometer and press the OK (F4) key to select
it. The Page Up/Page Down (F2/F3) keys below the display provide easy navigation if a large
number of thermometers has been created.
Press the key when the ‘Samples/Reading’ or ‘Readings in Stats’ settings are selected to
open a numeric entry window and specify a value. This may be quicker than using the 
keys to change the value:
Use the keys to move to a number button and select it using the key. As soon as
you start entering a new number, the original value is deleted. Press the OK (F4) key to apply
the new value.

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The ‘Samples/Reading’ setting is initially set to 1 but can be increased to a maximum of 100.
This will cause the milliK to take the specified number of samples for each reading and will
reduce the noise at the expense of slower measurement speed.
2.2.4 The ‘Instrument’ Window
In the ‘Instrument’ window you can access the milliK’s database of thermometers, perform
maintenance tasks (such as backing up, clearing or restoring information stored to internal
memory, updating software, calibrating your milliK), change the IP
address/passwords/date/time settings and define temperature profiles you wish to use when
calibrating thermometers with your Isotech temperature source:
Use the keys to select the required function and then press the key to open a new
window to access that function. Some functions are password protected, in which case a soft
keyboard will appear and you will be asked to enter the password before proceeding:

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Use the keys to move to a button and select it using the key. Press OK to enter
the password. A separate password is provided to protect the calibration of the milliK. Both
passwords are initially set to “1234” but should be changed prior to use in order to ensure
the security of measurements made using your milliK (see section 3.11). A password
recovery process is available if you forget your password, please contact Isothermal
Technology or its approved distributor for assistance if required (see section 3.11.1).
2.3 Battery Operation
The milliK is primarily intended for use as an AC powered, bench-top instrument and is
supplied with a universal power supply for this purpose. However, it may also be powered
from batteries (not supplied) so that it can be used where an AC electrical supply is not
available.
The battery compartment is located on the rear panel. To gain access, squeeze the tabs on
the sides of the battery drawer and slide it out. The battery compartment accepts four AA
size cells.
The milliK can use primary (alkaline or lithium) cells or rechargeable (NiMH) cells. Lithium
cells provide the longest battery life (>6 hours), but are expensive and are not rechargeable.
Rechargeable NiMH cells provide good battery life (> 4 hours) and being rechargeable offer
low running costs, they are therefore the recommended solution for users wishing to use the
battery powered option. Alkaline cells can be used, but they provide limited operating life;
tests have shown that alkaline cells offer half the operating life of NiMH cells with the same
quoted capacity (mAh) because they have a higher output impedance during discharge
(leading to a lower output voltage).

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3Detailed Description by Function
This section describes all the features available on the milliK by function. If you wish to learn
how to do something with your milliK use the table of contents on page 2 onwards to look
up the appropriate section.
3.1 Using a PRT/SPRT with milliK
The milliK can measure the resistance of PRTs and SPRTs. It can convert measurements
from resistance to temperature units (K, °C or °F) so that you can make precise temperature
measurements or calibrate other thermometers from a reference standard.
The milliK provides two resistance measurement ranges which are optimised for PRTs and
SPRTs:
0-115Ω: optimised for 25.5ΩSPRTs
0-460Ω: optimised for 100ΩPRTS
The milliK will measure 25.5ΩSPRTs on the 460Ωrange, but better measurement
uncertainty is achieved by using the 115Ωrange. The sense current for both ranges is 1mA
(or 1.428mA).
Connect your PRTs/SPRTs to either of the Lemo 6-pin circular connectors on the front panel
(see section 4.1 for pin-out and connection details). Ensure that the miniature thermocouple
connector for the same channel is unused (since it is connected in parallel with the Lemo
connector). Isotech can (optionally) supply thermometers fitted with a suitable Lemo
connector. Your milliK is supplied with two Lemo connectors for you to use with your own
PRT/SPRT (or thermistor). The part number for this connector is:
Lemo part number: FGG.1B.306.CLAD62Z
Additional connectors are readily available internationally from Farnell Electronics and can be
ordered via their website www.farnell.com (Farnell stock code 3817325).
Channels 1 and 2 are not isolated from each other, but are isolated from Channel 3 and from
the digital interfaces in order to optimise immunity to external noise sources.

©Isothermal Technology
Page 20 of 127
923 milliK manual Iss. 3.02
3.1.1 Configuring milliK to measure a PRT/SPRT
Press the Settings (F3) key to access the Settings window, which opens with the ‘Channel’
parameter selected. Use the keys to select the channel that you want to configure.
Then use the keys to select each parameter in turn and set it to the required value either
by using the keys to sequence through the options or pressing the key to open a
new window with all the options listed. A typical configuration for an uncalibrated PRT would
be:
‘Range’ would normally be set to 460Ωfor a 100ΩPRT and to 115 Ωfor a 25.5 ΩSPRT (see
section 3.1). Most PRT/SPRT measurements are made with a 1mA sense current, but this
can be increased to 1.428mA in order to determine the self-heating effect (see section 3.1.2).
The ‘Samples/Reading’setting is the number of samples averaged together to form a single
reading. Increasing this value will reduce the noise on the measurements (standard deviation
will reduce as the square root of the number of samples) but also slows down the update
rate.
Higher accuracy measurements can be made using calibrated PRTs/SPRTs whose resistance-
temperature characteristics have been determined. Before being used, the thermometer and
its calibration details must be entered into the milliK’s thermometer database (see section
3.9.1). The thermometer will then appear in the ‘Thermometer’ list. Use the keys to
sequence through the thermometers or press the key to open a new window with all
thermometers listed: