calibration

	general calibration
	calibration for digital recorders corresponding to IEC 1083-1
	calibration of impulse measuring systems corresponding to IEC 60-2
	D/A converter-card DAC 16

 

general calibration

The descriped programs TRAS-KAL and TRAS-TEIL don’t belong to the usual delivery of the software. If you have interests or need this parts of the software, you can purchase them if you contact the manufacturer or your appropiate representative.
For measurements or calibrations corresponding to IEC 1083-1 or IEC 60-2 you will need high-precision calibration-generators, which as far as possible should be adjusted to the digital-measuring system you want to calibrate. For this assignment there was developed  a whole family of new calibration-generators including the necessary software, which give you the ability to practice all claimed calibrations or measurements corresponding to IEC 1083-1 and IEC 60-2.
The impulse calibration system KAL 1000 is a modular system to calibrate impulse measurement systems for highvoltage-test technique.  The modular assembly of the system makes it possible to to build an optimal KAL-configuration from your defined needs.
The modularity allows to extend or reconfigure your KAL-system by growing or changing requirements. The technical design of the impulse-calibration system KAL 1000 considers the international standard IEC 1083-1, digital recorders for impulse voltage and current-measurements and the expected decision of the standard IEC 60-2 which is currently in revision.

calibration of digital recorders corresponding to IEC 1083-1

The calibration of several measuring ranges of digital impulse measurement systems TR-AS 25/8/10/12 or TR-AS 100/200.8/10/12 corresponding to IEC 1083-1 as “performance check”can either be done with an impulse-calibration or alternative with an extra calibration of voltage and time via step-voltage.

calibration software TRAS-KAL

The automatic control of impulse-calibration-systems is done via a coaxial connection which is connected to the calibration-relay of the digital impulse measurement system TR-AS.
The channels which you should be calibrated will be connected either alone or in parallel to the output of the calibration-generator.  
ATTENTION : Only connect outputs while dead.
The calibration is done after setting the calibration-voltage in all channels for that measuring range. The preset count of records is done automatically via control-relay of measurement system. The records will be evaluated corresponding to IEC 1083-1 (e.g. 20 records).
The maximum deviation and the mean-value of the choosen records will be saved into a protocol-file from which can be made the calibration-certificate later.
The base-device consists of a electronical controlled highvoltage loading device, which loads the output stage of the calibration-generator. The output-voltage can be set in a high-precision range between 0V and 1000V. The output of the base-device is a coaxial jack and there are two additional measurement jacks from which you can measure the output-voltage via an external high-precision voltage instrument.
Because of this there is the ability to back-annotate the measurements to a calibration-laboratory or the PTB (Physikalisch-Technische Bundesanstalt).
At the beginning of the automatic calibration-sequence, you must input the choosen value of the loading direct-voltage. This value is the reference for further calculations in the calibration process.

calibration digital-recorder

 please choose the application “recorder calibration” in WinTRAS.

There must be now an input-dialogue. In this dialogue you can select or create a new project / job. In this case there is no need to select a test-setup, display-view or recorder-setting.
Data, which describe the test-object like serial-no., date etc. can be input in this dialogue.

calibration-type and calibration-profile

Here you can select the used calibrator-type KAL 1000 and as profile-name the serial-no. of the used calibration-generator. The input “KAL 1000” without serial-no. defines a calibrator with standard parameters corresponding to IEC 1082-1. In “calibration-profile” you can input calibration-results of a calibration-generator. In dependence to the serial-no. e.g. KAL1000#190 you can additional select the calibrator-settings.

Creation of a calibration-profile
For each calibration-generator should be generated an own profile. For input of data you must first select the profile-name. We recommend to use the DKD-calibration protocol to create a profile and to use as profile-name the “KAL1000”+serial no. or “DKD”+calibration no.
For each impulse wave-shape you must input the load-voltage and the corresponding standard values from the calibration-protocol, where the data in rows with “+” must be input. The profile table works with lineare interpolation in the range “<=” of the input load-voltage borders, where the lower border is automatically set to 0.

impulse and measuring input
The wave shape and the meas urement input you want to calibrate  must be selected here.

start of the calibration / measurement range

After starting the calibration with “F8” or the corresponding toolbar button, there must be made some settings. The recorder can be calibrated in the measurement ranges with reference to the borders for voltage-range which are described in the calibration-certificate from KAL 1000. The measurement ranges which should be calibrated, can be selected after start of calibration in the follwing dialogue.

If the KAL 1000-unit is built into a measuring rack MIRA there is optional the opportunity to use a automatical voltage-control via control-card KAL-DAC16. KAL-DAC 16 is setting the voltage-load for the KAL 1000 automatically for all selected measurement ranges in the selected wave shape and polarity. Before start you should input the displayed load-voltage on KAL 1000-internal display which corresponds to the 1V output-voltage. The saved measuring results can later be output into a protocol.

impuls-calibration
The impulse calibration is done with the impulse-calibration generator KAL-LI 0,84/60 (optional with KAL-LI 1,56/60) for full or chopped lightning-impulse waveform or with impulse-calibration generator KAL-SI 20/4000 (optional with KAL-SI 250/2500) for full or chopped switching impulse waveform. The corresponding wave shape must be selected.

connection KAL 1000-LI and –SI
If you are using a positive impulse-voltage, there must be connected a short-circuit plug to the negative BNC-output jack. The positive BNC-output jack for LI or SI will be connected via a coaxial connection cable with the inputs of the digital impulse-measuring system which you want to calibrate.
ATTENTION: Only connect outputs while dead.

The voltage impulse-load will be transferred internal.
The trigger-input of the base-device (firing input) will be connected via coaxial connection cable with the control-relay output (control out) of the digital impulse-measuring system.
The amount of the pre-calculated impulse-voltage load will be displayed.  

The loading voltage must be chosen corresponding to the reference value at the KAL 1000 or the pre-calculated value of the measuring system must be edited if you aren’t able to set the value at the KAL 1000.
The record will be automatically started if you chosen “OK”, the calibration generator will be triggered and the measured impulse will be evaluated until the calibration of the measurement range is done (the amount of records you have chosen in input-dialogue will be recorded).

calibration with STEP-voltage
This calibration is done with step-voltage taken from the step-voltage generator KAL-STEP. The wave shape STEP must be selected in this case.

connection for KAL 1000-STEP
For negative STEP-voltage you must connect the BNC-output jack via a coaxial connection cable with the impulse measuring system you want to calibrate.
ATTENTION: Only connect outputs will dead.
The triggering-input of the KAL 1000 base-device (firing input) must be connected via coaxial connection cable with the control-relay output of the digital impulse-measuring system. Further information is given in “impulse calibration”

time calibration
The time-calibration will be done with a built-in high-precision timemark-generator. The wave shape TIME must be selected.

connection for KAL 1000-TIME
For the time-calibration the BNC-output jack TIME must be connected via a coaxial connection cable with the inputs of the digital impulse measuring system.

The triggering-input of the KAL 1000 base-device (firing input) must be connected via coaxial connection cable with the control-relay output (control out) of the digital impulse-measuring system. Further information is given in “impulse calibration”

calibration results

The calibration results will be saved into the WinTRAS-internal database und can be displayed in a result.list. The automatic IEC-check operation “CHECK IEC 1083-1” displays the maximum differences for each parameter filtered for the actual wave shape.

calibration protocol

First you can select the wave shapes you want to print.

If you have saved curves when you did your calibration, you can select the output of this graphics and several other options in this dialogue.
The output of the calibration results is done in tabular form beginning with the test-object data and following the calibrated wave shapes (as you can see in the small preview for the wave shape LI 0,84/60).

calibration of impulse measuring systems corresponding to IEC 60-2

This method is taken to determine the dynamical scale factors and the response parameters of the whole measuring system. This is done with the standard-jump method from IEC 60-2.

calibration of an impulse-voltage divider

The calibration of impulse measuring systems which consist of highvoltage-divider with connection, measuring cables and digital impulse-voltage measuring system TR-AS happens with the parameter-method taken with the rectangle-impulse geneator KAL 1000-RIG and the calibration software TRAS-KAL.

The generator is placed at the floor or at one wall in the test-field. The generator will be connected to the high-voltage divider and the measuring system as described in IEC 60-2.
ATTENTION : Only connect outputs while dead.
If you use positive impulse the negative BNC-output of the KAL 1000-RIG must be connected with a BNC short-circuit plug. The positive BNC-output jack must be connected with the high-voltage part of the divider (red). The ground must be connected to the earth of the impulse-circuit at the high-voltage divider (black).
The input for voltage-load must be connected when using a KAL 1000-RIG without internal HV-device via coaxial cables using special high-voltage plugs with a KAL 1000 base-device (not displayed).
The triggering-input must be connected using a coaxial cable (green) with the control-relay output of the digital measuring system.
The measuring cable from the divider (blue) will be connected to channel 1, input jack 10V of the digital measuring system. If some alternating zeroline-levels occur, which are caused through influences from the measuring circuit, you should supply both measuring system and the KAL1000 base-device from isolating transformer and not directly from power net.et.

Performance check

The parameter method used in “performance check” corresponding to IEC 60-2 measures amd evaluates the response to a dirac-impulse and from this the method can directly determine the dynamic scale factor and time-parameters. This values can be compared to data from the manufacturer or former as “performance tests” accomplished measurements.

Calibration software TRAS-TEIL

For the partly automated calibration and the full-autoamted creation of calibration-certificates there is the efficient software TRAS-TEIL at disposal, which has a user-friendly menu guidance.
The determination of dynamic scale factors and response parameters of the overall system corresponding to IEC 60-2 takes the rectangle-impulse generator KAL-RIG and uses a repetitive sampling-method, which enables sampling-rates between 1 and 5 GHz with the digital recorders TRAS 100/200-8/10/12. This method is built into the calibration software TRAS-TEIL.
The automated control of impuls-calibration systems is done with the help of  a digital impulse-measuring system TR-AS with built-in or additional control-relay.
In this case firstly the response g(t) of the impulse-measuring system is determined, while a sampling-factor of 10 when using 200 MS/s and/or 20 when using 100 MS/s sampling-frequency corresponds to a total sampling-frequency of 2 GHz (this is a time-resolution of 500 ps). This method gives very good accuracy while short test-time.

Options

Application „divider calibration“ should be chosen. Please select or create a  project/job and input the relevant data for the test-object. As test-setup there will be automatically chosen „REP“ from the software.

- choose measuring and triggering channel with channel 1
- choose target channel with channel 7
- choose as input range either 10V or 1600V according to the magnitude 
  of response you expect due to the divider-ratio
- choose trigger-level in the middle of the linear rise of the impulse you want to measure
- Input the divider-ratio of your high-voltage divider
- Measuring range : this should be approximately 150 % of the voltage-load 
  in dependence of the overshot of your  divider
- Zero-line : approximately 10% when using positive impulse and 90% when using negative impulse

- select wave shape
- Consider that KAL 1000 is providing a positive voltage which is shorten (=STEP)
- Consider that RIG 1000 is providing a positive or negative voltage which is an impulse (=IMP)
With „START“ the automatic determination of the response is started.

Evaluation

  Calculation of the „response paramters“ is done from the response g(t)

In the form „eveluation“ there must be displayed the evaluation type „RESP“ in channel 7. The calculation of „response paramters“ from response g(t) and the time-process for response time T(t)  is done as integral of the function „ 1 – g(t) “ automatically through internal computer of the measuring system.  

Resp - impulse response evaluation

You should take care of the calculation of settling time ts because this is especially dependent of the choosen border tmin. If tmin is chosen to small you will possibly get bigger settling times ts.
Result of the divider-calibration can also be taken as references. This paramters can be taken for later „perfomance checks“ as comparison. If displaying response parameters you can edit the border-values.

D/A converter-card DAC 16

The DAC 16-card is used in one ISA-slot of the measuring systems’s internal control-computer. It works with a resolution of 16 bit and outputs high-precision direct-voltages. There are two output-ranges : -2 V ... +2 V and –10 V... + 10V

This additional hardware must be configured using the WinTRAS-configuration tool as displayed in following picture.
The output-voltage is available at the BNC-jack „DAC OUT“. The second BNC jack " REL " is connected with a relay contact, which switches with triggering after mass (here not used). The card can be taken to control the voltage-load of the calibration generator KAL 1000.
For this purpose one connects the BNC bush " DAC OUT " and/or.  „U-Out "over the provided adaptor cable with the DB9-connector "control" at the rear side of the calibration generator.
If you want to trigger the calibration generator by software-control, you have to connect the BNC jack „REL OUT“ of the measuring system via coaxial cable with the jack „external trigger“ at the front panel of the KAL 1000.

The control for voltage-load of the calibration generator KAL 1000 is done full-automatic while calibrating with calibration software TRAS-KAL.
After start of calibration you have to input the measured voltage-load of KAL 1000 while output is 1V. This is done to compensate the small offset-error  of  DAC 16.  

The voltage-load of the calibration generator can additional be controlled by small tool „DAC 16-help“ which directly sets output-voltage of DAC 16-card.
In this case the dependence is :
- voltage-load KAL 1000 = Ua (DAC 16)*100
- display (as you can see in picture above) corresponds to voltage-load of 387,5 V.

ATTENTION :
If you work with the KAL 1000-generator you should only set positive DAC 16-output voltages.
The high-precision voltage-output of the DAC 16-card and the control-input of the high-voltage generator built-in KAL 1000 base-device is only conditionally protected against overvoltages.
The use of this system can only be done if KAL 1000 is built into a shielded measuring rack MIRA 25.
With application in table housings DERA 6 and separate KAL 1000 this control line as well as all other electrical connections (printers...) are to be removed reciprocally, in order to prevent electrical influence or destruction from measuring system or Kalibrator with impact tests.
For such errors we cannot take over a guarantee!