Isotech milliK Скачать руководство пользователя страница 26

Страница: 26 / 102

Page 26 of 102

923 milliK manual - issue: 1.10

3.3.1 Using Internal Reference Junction Compensation

The EMF developed by a thermocouple depends on the temperature difference between the

measurement and reference junctions. It is therefore necessary to know the temperature of the

reference junction (the point at which the electrical circuit changes to copper) in order to

calculate the temperature at the measurement junction. The milliK measures the temperature

of the contacts in the miniature thermocouple connectors on the front panel so that these can

be used as the reference junction in the thermocouple system. In this arrangement there is no

externally accessible reference junction and wires that make up the thermocouple are

connected to the milliK using a connector made of the same material as the wire itself. It is

essential that the correct “typed” connector is used with the thermocouple:

Reference

Measurement

Junction

M+

M-

When using a thermocouple with internal reference junction compensation, the ‘Reference’

parameter in the

Settings

Window should be set to “Internal” (see section 3.3.4).

For greater accuracy, you can use an external reference junction whose temperature is

measured with a calibrated thermometer (see section 3.3.2) or that is immersed in an ice-point

at 0°C (see section 3.3.3).

3.3.2 Using External Reference Junction Compensation

The milliK allows you to measure the temperature of an external reference junction using a

thermometer connected to another channel. This technique can provide better measurement

uncertainty (than using internal reference junction compensation, see section 3.3.1) provided

that the reference junction and sensing thermometer are adequately isothermal and that the

reference junction thermometer is sufficiently accurate:

Содержание milliK

Страница 1: ...x 44 0 1704 544799 Internet Tel 44 0 1704 543830 Fax 44 0 1704 544799 Internet Tel 44 0 1704 543830 Fax 44 0 1704 544799 Internet Tel 44 0 1704 543830 Fax 44 0 1704 544799 Internet www isotech co uk w...

Страница 2: ...h milliK 30 3 4 1 Configuring milliK to Measure a 4 20mA Transmitter 31 3 5 Measuring the Difference Between Two Channels 32 3 6 Changing Graph Scales 32 3 7 Using Rolling Statistics 33 3 8 Logging Re...

Страница 3: ...Voltage Offsets 69 5 3 6 Adjusting Voltage Gain 69 5 3 7 Adjusting 4 20mA Transmitter Range 70 5 3 8 Adjusting the RJC Sensor Calibration 71 5 4 Exporting Calibration information 72 6 Maintenance and...

Страница 4: ...CALibrate RESistance GAIN 92 8 6 28 Command CALibrate VOLTage OFFSet channel 92 8 6 29 Command CALibrate VOLTage OFFset channel 93 8 6 30 Command CALibrate VOLTage GAIN 93 8 6 31 Command CALibrate VOL...

Страница 5: ...ides a simple and intuitive operator interface and with a wide range of interfaces USB RS232 Ethernet allows the user to access the comprehensive features of the milliK 1 1 Unpacking Your product shou...

Страница 6: ...ndoor 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...

Страница 7: ...gy Page 7 of 102 923 milliK manual issue 1 10 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...

Страница 8: ...cal 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...

Страница 9: ...ials are available on the Isotech website see www isotech co uk video library php 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 c...

Страница 10: ...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 The milliK is also equipped with two RS232 ports these are c...

Страница 11: ...lliK 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 Wi...

Страница 12: ...he 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 o...

Страница 13: ...e 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 yo...

Страница 14: ...elect 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 setti...

Страница 15: ...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 passwo...

Страница 16: ...ed 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 secti...

Страница 17: ...attery 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 a...

Страница 18: ...but better measurement uncertainty is achieved by using the 115 range 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 th...

Страница 19: ...rements 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 aver...

Страница 20: ...Select the thermometer and set the remaining parameters in the Settings Window A typical configuration for a calibrated SPRT would be Once you have configured the milliK to work with your PRT SPRT pre...

Страница 21: ...urrent and observing the change in indicated temperature The milliK provides a feature that allows the sense current to be increase by a factor of 1 428 mA which increases the power dissipated by a fa...

Страница 22: ...between V and V pins 1 and 6 to determine the voltage across the PRT element In this way the milliK is able to perform a 3 wire measurement that is substantially immune to the resistance of the wires...

Страница 23: ...e of screened cables is highly recommended see section 4 2 Unlike PRTs SPRTs the resistance temperature characteristics vary considerably between different types of thermistor There are therefore no n...

Страница 24: ...ameter 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 fo...

Страница 25: ...ata to a file 3 3 Using a Thermocouple with milliK The milliK can be used with any thermocouple calibrated or uncalibrated fitted with a standard miniature thermocouple connector Connect your thermoco...

Страница 26: ...of the same material as the wire itself It is essential that the correct typed connector is used with the thermocouple Reference Measurement Junction Junction M M When using a thermocouple with inter...

Страница 27: ...a Conversion defined appear in the Reference parameter list Thermocouple channels do not appear in the Reference parameter list in order to avoid circular dependencies For greater accuracy you can im...

Страница 28: ...ith calibration data set Thermometer to Default Thermocouple If you want to use temperature units select one of the standard conversions for thermocouples If your thermocouple is supplied with calibra...

Страница 29: ...point as the reference junction see section 3 3 3 A typical configuration for a calibrated gold platinum thermocouple entered into the database as AuPt thermocpl and using an ice point reference woul...

Страница 30: ...sockets on the rear of the milliK designated Channel 3 The centre 4mm socket is the current sense input to the milliK the other 4mm sockets are 0V and a 24V supply Connect the transmitter between the...

Страница 31: ...with the Channel parameter selected Use the keys to select Channel 3 and then use the keys to select each parameter in turn and set it to the required value either by using the keys to sequence throug...

Страница 32: ...is available in both the Graph or Numeric Windows where the differential option is listed amongst the other single channels on the Channel x button or in the channels list that open when this button...

Страница 33: ...nd cannot be selected Change this to Manual in order to access these parameters by selecting the Automatic Manual button and pressing the key 3 7 Using Rolling Statistics The milliK reports the mean a...

Страница 34: ...The milliK can store results to a file on an external USB drive connected to the USB port on the rear of the instrument or to internal flash memory Files stored to internal memory can be transferred t...

Страница 35: ...his opens the File Location Window Use the keys to select whether to store the file to external or internal memory and then press the OK F4 or keys to open a soft keyboard and enter a filename a defau...

Страница 36: ...is the serial number of the milliK If the files already exist on the USB drive a Window will open allowing you to specify whether or not to overwrite each file you can specify whether or not to overwr...

Страница 37: ...4 Wire PRT Default 4 Wire PRT Serial Number Recalibration Date 31 12 2099 31 12 2099 31 12 2099 Minimum Temperature 273 15 273 15 0 Maximum Temperature 2000 2000 200 Temperature Conversion None IEC607...

Страница 38: ...readings to temperature conversion type and coefficients minimum and maximum operating temperature and identify whether it uses 3 or 4 wire connection PRTs only Thermometers in the database will appe...

Страница 39: ...ue 1 10 Use the keys to select Create New Thermometer and press the key to open the Thermometer Window Use the keys to select each parameter in turn and press the key to open a Window and enter a valu...

Страница 40: ...ith temperature for platinum is well know and predictable The characteristics depend on a number of factors including the purity of the wire Higher purity platinum wire exhibits greater sensitivity mo...

Страница 41: ...ristics determined in order to achieve low uncertainties There are two algorithms used to represent the thermometer s characteristic the Callendar Van Dusen equation and the ITS90 equations The Callen...

Страница 42: ...temperature These equations commonly referred to as ITS90 comprise a nominal conversion that represent the average conversion characteristic and deviation functions that provide the adjustment for the...

Страница 43: ...can then be entered below the button 3 9 5 Using a Thermocouple with Calibration Coefficients Data Pairs The EMF temperature characteristics of thermocouples are non linear and the milliK uses standa...

Страница 44: ...elete a data point use the keys to select the point and press the Delete F2 key The 0 0 000 point is fixed and cannot be deleted Do not use the thermocouple outside the temperature range defined by th...

Страница 45: ...numeric keypad and enter the required value 3 9 7 Using a Thermistor with Polynomial Temperature Conversion The Steinhart Hart equation uses a third order polynomial with the second order term missin...

Страница 46: ...inimum output value and 20mA indicates the maximum Current below 4mA is often used to indicate a fault condition in the transmitter To use linear interpolation of the current and determine the measure...

Страница 47: ...s that are found on the USB drive and give you the option to implement the update before restarting the software The software is divided into two parts The first is designated software and provides th...

Страница 48: ...ress the Instrument F4 key use the keys to select Change Password and then press the key to open the Password Selection Window Use the keys to select which password you wish to change and then press t...

Страница 49: ...ill send you a temporary password to enable you to change the password to a new value Enter this temporary password as the Old Password in the Change Password Window Once you have changed the password...

Страница 50: ...ows you to select a temperature profile or disable this feature by selecting None Temperature profiles can be created in the Instrument Window see section 3 12 1 Use the keys to select the Setpoint Te...

Страница 51: ...Profile The milliK allows you to define temperature profiles and store these in a database To create a new profile press the Instrument F4 key use the keys to select Setpoint Temperatures and then pr...

Страница 52: ...ey whilst Immediate is selected to toggle between Immediate profile starts as soon as the OK F4 key is pressed when the profile is selected and On Save profile starts when you start logging data with...

Страница 53: ...LAD62Z Additional connectors are readily available internationally from Farnell Electronics and can be ordered via their website www farnell com Farnell stock code 3817325 The pin out of the Lemo conn...

Страница 54: ...hould be of the same resistance of same length and gauge and connected directly to I and I pins 2 and 3 and a link that carries no current should be made from pin 1 to pin 2 see section 3 1 3 4 5 6 1...

Страница 55: ...5 6 1 2 I I V V 3 tc THERMISTOR NC NC 4 3 Connecting Thermocouples to milliK In order to connect thermocouples to your milliK fit a suitable miniature thermocouple plug conforming to ASTM 1684 05 and...

Страница 56: ...20mA transmitter to your milliK fit 4mm plugs to your transmitter The milliK supports both self powered and loop powered transmitters by providing a 24V DC supply Connect the transmitter to the 4mm s...

Страница 57: ...milliK then making any necessary calibration adjustments and finally checking the calibration after adjustment The calibration should be checked or adjusted in a temperature controlled environment be...

Страница 58: ...10mA source to calibrate the 4 20mA input using a calibrated 10 resistor to generate the signal offers a reliable and inexpensive solution A calibrated 10 resistor for use with the 10mA source to gene...

Страница 59: ...g and short together the two pins of the connectors with a short length of copper wire The copper wire should remain inside the connector housing be as short as possible and go directly between the tw...

Страница 60: ...s and provides an inherently stable zero for resistance measurement There is therefore no zero adjustment for resistance and the zero check is only used to confirm correct operation of the milliK Appl...

Страница 61: ...e resistor if its temperature coefficient of resistance is significant Repeat the procedure on Channel 2 5 2 1 3 PRT Resistance Range 460 Span Check Connect a calibrated nominally 400 resistor to chan...

Страница 62: ...e of the resistor apply a correction to the value of the resistor if its temperature coefficient of resistance is significant Repeat the procedure on Channel 2 5 2 3 Thermocouple Voltage Range Zero Ch...

Страница 63: ...tirely in copper and should not involve intermediate connectors to avoid thermal EMFs Set the milliK to read this voltage by changing the parameters in the Settings Window see section 5 2 3 for detail...

Страница 64: ...o it is likely that you will see the readings dithering between 2 values separated by the milliK s current resolution 0 001mA The mean value indicated by the milliK should be compared with the current...

Страница 65: ...t 20 C might be 5 V or even higher which corresponds to a temperature error of approximately 0 2 C An alternative approach would be to use room temperature as the known temperature and to measure this...

Страница 66: ...s calibration software that allows you to adjust all the calibration parameters Adjustment simply requires you to attach reference standards calibrated resistors voltage source or current source to th...

Страница 67: ...2 Adjusting SPRT 115 Resistance Range Connect a calibrated nominally 100 resistor to channel 1 In the Calibration Menu Window use the keys to select 115 Range and then press the key to proceed to the...

Страница 68: ...ess cannot be aborted 5 3 3 Adjusting PRT 460 Resistance Range Connect a calibrated nominally 400 resistor to channel 1 In the Calibration Menu Window use the keys to select 460 Range and then press t...

Страница 69: ...Once started the calibration adjustment process cannot be aborted Repeat the procedure on Channel 2 5 3 6 Adjusting Voltage Gain Connect a calibrated nominally 100mV signal to channel 1 see section 5...

Страница 70: ...4 20mA Transmitter Range Connect a calibrated nominally 10mA current source to the 4mm sockets designated channel 3 on the rear of the milliK 10mA Calibrated Current Source In the Calibration Menu Wi...

Страница 71: ...n 3 3 4 If you measure the ambient temperature with a calibrated PRT and use this as the known temperature for the calibration see section 5 2 6 for details you can reasonably use a good quality uncal...

Страница 72: ...ion information A calibration file containing the complete calibration history of the milliK in comma separated CSV form can be exported to a USB drive for transfer to a PC The file can be imported in...

Страница 73: ...little mild liquid soap on a lint free cloth to clean your milliK Dry the screen and touch panel immediately after cleaning with a lint free cloth Never use abrasive cleaners such as cream cleaners or...

Страница 74: ...were to connect separate PCs to the two COM ports then measurements made by software running on one PC would not affect measurement made by the other PC There is of course only one measurement system...

Страница 75: ...Connect your milliK to a PC using the null modem RS232 cable supplied If you wish to make your own cable use the following arrangement 1 2 3 4 5 6 7 8 9 Shell 1 2 3 4 5 6 7 8 Shell 9 Null Modem Cable...

Страница 76: ...RS232 connection with your milliK Type IDN into Hyperterminal terminate the command by pressing the carriage return or Enter keys the milliK should then respond with a string in the form Isothermal Te...

Страница 77: ...panel to your LAN using a standard non cross over patch cable Then launch the CE6 cerhost exe application this Microsoft freeware application can be downloaded from http isotech info milliK Click on...

Страница 78: ...ection and display the screen as it appears on your milliK Click Tools Config and select the Whole Screen radio button in the Update area to ensure that the screen remains synchronised with your milli...

Страница 79: ...should be terminated with a Carriage Return character ASCII character 13 Responses from the milliK are always terminated by a Carriage Return character 8 2 SCPI Command Structure Commands are arranged...

Страница 80: ...the command MEASure SCALar VOLTage DC Valid forms of this command include MEAS VOLT MEASURE SCALAR VOLTAGE DC 8 3 SCPI Numeric Suffices In order to support multiple input channels commands can includ...

Страница 81: ...king Measurement Using SCPI Commands The milliK s measurement system can be controlled by SCPI commands from either of the RS232 ports The software makes no distinction between commands received on ei...

Страница 82: ...f 80 using the normal 1mA sense current send the following command sequence SENS CHAN 1 SENS FUNC RES SENS WIR 4 SENS RES RANG 80 CURR NORM READ The milliK will then report the measured resistance for...

Страница 83: ...in temperature units using SCPI commands However it is possible to set up measurement s using the operator interface and then to access the results using SCPI commands To do this simply setup your mi...

Страница 84: ...Isothermal Technology Page 84 of 102 923 milliK manual issue 1 10...

Страница 85: ...hannel RESistance channel resistance range current wires CURRent RJC MONitor channel timeout CALibrate UNLock password LOCK RESistance GAIN resistance range current gain standard RESistance GAIN resis...

Страница 86: ...hermal Technology milliK ITL12345 1 22 33 8 6 6 Command SENSe FUNCtion ON Format SENSe FUNCtion ON function Selects the measurement function The parameter function must be one of the following valid S...

Страница 87: ...surement will respond to SENS CHAN with 1 8 6 10 Command SENSe RESistance RANGe UPPer Format SENSe RESistance RANGe UPPer range Sets the range for the next resistance measurement The 3 resistance rang...

Страница 88: ...to make a 4 wire resistance measurement will respond to the command SENS RES WIR with 4 8 6 14 Command SENSe CURRent Format SENSe CURRent current Determines whether the normal 1mA or root2 1 4mA curre...

Страница 89: ...n defined with SENSe commands such as SENS CHAN 1 SENS FUNC volt use INIT 8 6 17 Command FETCh SCALar Format FETCh SCALar Reports the result of the last measurement made Example a milliK that has made...

Страница 90: ...el number as this command makes use of the numeric suffices feature of SCPI described in section 8 3 The reported value is in ohms This command is equivalent to SENS FUNC RES SENS CHAN channel SENS RE...

Страница 91: ...it reports Channel Not Enabled The milliK reports the value followed by the units separated by a comma Where units R for ohms mV for milli volts K for Kelvin C for C F for F Example if channel 2 is c...

Страница 92: ...re a resistance gain of 1 001234 for the resistance range 0 460 with normal 1mA sense current by using a resistance standard with serial number xyz1956 the gain can be set using CAL RES GAIN 460 NORM...

Страница 93: ...standard and additional info parameters are strings that are stored in the calibration database file which can be exported to a USB flash drive see section 5 4 to provide information about this calibr...

Страница 94: ...ber xyz1956 the gain can be set using CAL CURR GAIN 1 001234 SN_xyz1956 or CAL VOLT GAIN 1 001234 8 6 33 Command CALibrate CURRent GAIN Format CALibrate CURRent GAIN Reports the current measurement ga...

Страница 95: ...temperature Sets identification information used to stamp any calibrations that are made after this command until the milliK is restarted This information would typically be used to store information...

Страница 96: ...This is initially set to 1234 but should be changed before using the milliK for any critical or traceable measurement or calibration work The new password must be at least 4 characters in length and...

Страница 97: ...Type N 600 C 0 04 C 0 06 C Type R 1000 C 0 09 C 0 12 C Type S 1000 C 0 10 C 0 14 C Type T 200 C 0 02 C 0 03 C Au Pt 600 C 0 06 C 0 08 C Thermocouples internal reference junction compensation Type B 1...

Страница 98: ...her than an ice point reference the total accuracy also depends on the slope of the V T curve at the reference junction temperature typically around 20 C The temperature accuracy figures for thermocou...

Страница 99: ...Isothermal Technology Page 99 of 102 923 milliK manual issue 1 10 x axis measured temperature in C y axis temperature accuracy on C...

Страница 100: ...ctive 93 68 10 2FCC Statement This equipment has been tested and found to comply with the limits for a Class A digital device pursuant to part 15 of the FCC Rules These limits are designed to provide...

Страница 101: ...for FCC compliance Conducted Emissions EN61326 2006 CFR47 2009 Radiated Emissions EN61326 2006 CFR47 2009 Conducted Immunity EN61326 2006 Radiated Immunity EN61326 2006 Electrical Fast Transients EN6...

Страница 102: ...ry Change Note Date Manual Issue Initial release April 2011 1 01 CN11008 17 06 2011 1 02 CN12002 07 02 2012 1 03 CN 12013 16 05 2012 1 04 CN 12014 30 05 2012 1 05 CN 12029 08 11 2012 1 06 CN 13013 21...

Результаты поиска

Содержание milliK

Отзывы:

Бренды по названию

Популярные бренды

Isotech milliK, Руководство по эксплуатации пользователя

Результаты поиска

Содержание milliK

Отзывы:

Бренды по названию

Популярные бренды