Vitrek 944i Operating & Maintenance Manual
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Vitrek 944i Operating & Maintenance Manual

Dielectric analyzer
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Advanced Test Equipment Rentals
www.atecorp.com 800-404-ATEC (2832)
944i Dielectric Analyzer
Operating & Maintenance Manual
Vitrek Corporation
9880A Via Pasar, San Diego, CA 92126
USA
V: 858 689 2755
F: 858 689 2760
Copyright Vitrek Corporation 1992-2008, all rights reserved, rev 2008-04-23
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  • Page 1 Advanced Test Equipment Rentals www.atecorp.com 800-404-ATEC (2832) 944i Dielectric Analyzer Operating & Maintenance Manual Vitrek Corporation 9880A Via Pasar, San Diego, CA 92126 V: 858 689 2755 F: 858 689 2760 Copyright Vitrek Corporation 1992-2008, all rights reserved, rev 2008-04-23 Table of Contents...

  • Page 2: Table Of Contents

    Introduction ......................1 Certification & Warranty Statement ...............1 Safety Precautions ....................2 1 Getting Started Unpacking.......................3 Initial Adjustments....................3 Front Panel Layout ....................4 Rear Panel Layout....................5 Instructions for Bench Use ..................6 Instructions for Rack Mounting ................6 Earth Ground Connection ..................6 Current Detection Circuitry ..................6 2 Direct Mode Operation DC Dielectric Strength Testing................7 AC Dielectric Strength Testing................8...
  • Page 3 6 Remote Operation Option IF-4 Interface Card Description ..............31 IEEE-488.2 (GPIB) Programming................31 RS-232C Communication Port ................38 Parallel Printer Port....................39 Vitrek Instrument Control Loop (VICL) ..............39 7 Options and Accessories Description of Optional Items.................40 8 Maintenance Routine System Inspection and Maintenance ............42 Verification Procedure....................43...

  • Page 4: Introduction

    Introduction The Vitrek 944i Dielectric Analyzer combines the four basic dielectric tests into one compact, easy to use, feature-rich instrument. The 944i's standard multi-function capabilities include - AC and DC Dielectric strength testing, Insulation Resistance (IR) measurement to 100 gigaohms and Earth Continuity measurement down to 10 milliohms. All of these tests can be run in either manual or automatic mode, as well as, via remote control using the optional IEEE-488.2 (GPIB), RS-232C or parallel...

  • Page 5: Safety Precautions

    DANGER! HIGH VOLTAGE Use extreme caution when working with high voltages. Never remove or insert test leads from the 944i while high voltage is present. Only use test lead materials which have adequate high voltage ratings. Inspect test leads regularly for signs of wear and abrasion.

  • Page 6: Unpacking

    Even if the instrument appears undamaged, it may have suffered internal damage in transit that may not be evident until operated or tested to verify performance. If the instrument fails to operate, notify the carrier's agent and Vitrek or your local Vitrek Service Center.

  • Page 7: Front Panel Layout

    L.E.D. Indicators - The 944i is equipped with 10 front panel L.E.D. status indicators. They are (from top to bottom): High Voltage Present, High Voltage Enabled, Testing, VICL Port Active, Printing, RS232 Active, GPIB Remote, Talk, Listen and SRQ (remote service request).

  • Page 8: Rear Panel Layout

    9. Chassis Ground Terminal 5. RS232 Port Fan Filter Assembly - The 944i uses a removable fan filter to clean the air used for cooling. Refer to the maintenance section of this manual for instructions on periodic removal and cleaning.

  • Page 9: Instructions For Bench Use

    Optional rack mounting brackets are available for mounting the 944i in a standard 19" equipment rack. The size and weight of the 944i require that the unit should be supported on both sides along its entire length by the use of trays or slides. If it is to be transported while mounted in a rack, it must be supported to prevent upward or downward movement.
  • Page 10 Operating the Vitrek 944i in direct mode permits the user to manually control the output up or down while monitoring the leakage current being drawn by the load. When operating in the direct mode the user is in full control of the measurement process - ramp rate and dwell time are a function of how fast the user changes the output voltage and how long the user chooses to stay at that setting.

  • Page 11: Ac Dielectric Strength Testing

    START TEST Upon pressing the enter key the 944i will sound a number of warning beeps while flashing the HV enable indicator. If the user has enabled the auto-ground test feature of the 944i, the unit will automatically check the chassis of the DUT for earth ground continuity before applying high voltage to the DUT.
  • Page 12 After the voltage limit has been set the 944i will prompt for a test frequency. This advanced feature, which enables the user to test AC dielectric strength over a wide range of test frequencies, is unique to the Vitrek 944i. The frequency prompt is as follows:...
  • Page 13 (giga) or K (kilo) use the up down cursor arrows. As in AC and DC, the Megaohm function of the 944i requires a two-step key press sequence that the device under test is properly connected to the 944i test terminals. Please refer to the "Test Connections" section of the operating manual before proceeding.
  • Page 14 LOW OHM TEST DIRECT AUTOMATIC To conduct manual low resistance measurements, select the direct option. The 944i uses a 2-wire measurement technique. Proper zeroing of test lead resistance is essential to obtaining reliable results. To facilitate the canceling of lead wire...
  • Page 15 The 944i will measure the lead resistance and store the value in non-volatile memory. Until a new value is stored the 944i will use this value to offset the lead resistance each time a low ohms test is done. In the event that the lead resistance is too high or a poor contact is made, the 944i will advise the user to check leads.
  • Page 16 10.0 SECONDS The test time is the amount of time that the 944i will hold the test voltage once it has arrived at that voltage. This period is often referred to as dwell time. During the dwell time the unit continuously monitors leakage current against both min and max current limits, while holding the output constant.
  • Page 17 10.0 SECONDS The test time is the amount of time that the 944i will hold the test voltage once it has arrived at that voltage. This period is often referred to as dwell time. During the dwell time the unit continuously monitors leakage current against both min and max current limits, while holding the output constant.
  • Page 18 As in direct mode testing, the automatic mode of the 944i requires a two step key press sequence prior to initiating high voltage testing. Before beginning this sequence, it is important to insure that the device under test is properly connected to...
  • Page 19 10 SECONDS The test time is the amount of time that the 944i will hold the test voltage after it has ramped up to that voltage. Test time is also referred to as dwell time. During the dwell time the unit continuously monitors insulation resistance. If at any time during either the ramp or dwell period, the minimum limit is exceeded the test is aborted and the DUT is failed.
  • Page 20 START TEST Upon pressing the enter key the 944i will sound a number of warning beeps while flashing the HV enable indicator. If the user has enabled the auto-ground test feature of the 944i, the unit will automatically check the chassis of the DUT for earth ground continuity before applying high voltage.

  • Page 21: Adding Test Steps

    Adding Test Steps The 944i is capable of storing up to 99 test programs with a maximum of 200 test steps. The maximum number of steps in any one test is 50. When operating the 944i in the automatic mode, after each step the following prompt is provided:...

  • Page 22: Recalling Tests

    Enter a program number between 0 and 40. The 944i will automatically search the test program database and display the next available program number. If the next available number is the desired test program number, press enter. After the program...

  • Page 23: Printing Test Reports

    QUIT PRINT RETEST If your 944i has the optional IF-4 remote interface package, then it is supplied with a built-in parallel port. For information on printer port configuration refer to section 6 - Remote Operation, Parallel Port. To obtain a listing of the test results, connect a PC compatible parallel printer to the 944i rear panel parallel port and press enter.
  • Page 24 Advanced User Note To increase throughput and reduce the number of keystrokes required to achieve the desired results, whenever multiple choices are offered in a menu selection each choice has a corresponding number. The items are numbered from left to right. For example if the "retest"...

  • Page 25: Test Connection Safety Precautions

    Dielectric Testing (VAC, VDC and I/R) All dielectric tests are performed from the 944i's V HI and V LO terminals. The V HI terminal is floating, while the V LO terminal remains relatively close to chassis ground at all times.

  • Page 26: Connecting To Earth Grounded Devices

    When testing devices which are not equipped with an earth grounded chassis, it is necessary to disable the automatic chassis ground test feature of the 944i. Otherwise the unit will fail the pretest auto-ground check and no further testing will commence.
  • Page 27 (DUT). For ease of connection Vitrek offers the TL-IEC shown above, which plugs directly into an IEC 320 style power inlet. For devices using a NEMA 5-15 (North American) power plug the available TL-115-50 provides for quick and convenient connection.

  • Page 28: Typical Electrical Safety Test Connection

    The Vitrek 944i Dielectric Analyzer has been designed to provide maximum user safety, reliability, and test throughput. To achieve this, the 944i is equipped with built-in self test capability, and a variety of user configurable test options. This section of...
  • Page 29 CAL DATA OK In the event of a cal data problem, the 944i will indicate that an error has been detected and that it is operating on default cal data. The unit should be referred to qualified maintenance personnel for calibration and inspection of the CMOS RAM battery, which has a five-year rating.

  • Page 30: Setting System Clock

    To configure the arc detect sensitivity, press the "CNFG" key and select the "SAFETY" option and then the “ARC” option. The arc detection feature enables the 944i to sense the presence of arcing before catastrophic damage occurs to the DUT. The arc...

  • Page 31: Ramp Current Limit

    Ramp Down Option A dielectric test is normally over when the end of the dwell time has been reached. In the default mode, the 944i will record the final leakage value then reduce the output voltage as rapidly as possible. Some applications require that the test voltage be ramped down at the same rate it was ramped up and that the current level is monitored during the entire descent.

  • Page 32: Safety Interlock

    “STEP” mode - which uses the short circuit to initiate testing then pauses and prompts the operator to interrupt the short circuit condition (allowing the operator to select a new DUT test point if desired), the 944i will automatically begin the next step of the test upon circuit closure.

  • Page 33: Command Syntax

    ***NOTE*** Previous versions of the manual indicate that a 2000 V/S ramp rate can be used. The 944i will accept it, but this is for a special engineering mode where the ramp rate will be uncontrolled and the unit will not return a proper response to the “RDNG?”...
  • Page 34 OUTPUT @V944;"RSLT?;" ENTER @V944;R$ PRINT R$ BEEP STOP ADD, {VDC} This command loads a single step test into the 944i's test buffer. The added test may then be run with the RUN command. Arguments: <VDC>, Selects DC Volts function <test voltage>,...
  • Page 35 OUTPUT @V944;"RSLT?;" ENTER @V944;R$ PRINT R$ STOP ADD, {MEG_OHM} This command loads a single step test into the 944i's test buffer. The added test may then be run with the RUN command. Arguments: <MEG_OHM>, Selects MEG_OHM function <test voltage>, 100 - 5000 V <slew rate>,...
  • Page 36 <min resistance>, 0 – 0.999 ohms <test time>; 1 - 999 S Example: ! File: T2.IBW ! This test sends a LO_OHM command to the 944i, waits ! for test completion, and then returns the results DIM Result$[120] ASSIGN @V944 TO 1410 REMOTE @V944...
  • Page 37 Function: Sends present current reading, in scientific notation, to the GPIB buffer. TTRIG? Argument: <none> Function: Valid when failure occurs during the dwell period of the test. The 944i sends elapsed time into the dwell when failure occurred, in floating point format, to the GPIB buffer.
  • Page 38 FTRIG? Argument: <none> Function: Valid when failure occurs during the ramp-up period of the test. Sends output voltage at time of failure, in floating point format, to the GPIB buffer. IMAX Argument: <max current limit> Function: Changes max current limit to a new value prior to or during a test. The new maximum current limit must be greater than the existing minimum current limit.
  • Page 39 <\n> (ASCII code 10) to terminate all commands through the serial interface. READ TERMINATOR The 944i will terminate all commands with a line feed character <\n> via the GPIB interface. ****NOTE: There is currently no read terminator added to responses via the serial port.

  • Page 40: Parallel Printer Port

    The RS232 connector on the rear panel of the 944i is a 9 pin female sub-D type. The most common type of connector found on a modern PC serial port is a 9 pin male sub-D type. The pinout of the 944i is designed to mate directly to a PC serial port using a straight through 9 pin male to 9 pin female extension type cable.
  • Page 41 944i. In order to ensure compatibility with various types of printers, the user may change the line terminator that the 944i sends to the printer.
  • Page 42 RM-1 Rack Mount Kit The RM-1 permits the 944i to be used in a standard 19" rack. Instructions for installing the RM-1 are provided in the "Getting Started" section of this manual.

  • Page 43: Routine System Inspection And Maintenance

    DC-7 7kV DC output Increases DC output range to 7kV DC (with decreased current limits). DC-7 option does not affect AC output specs. No external boxes or circuitry are necessary. DC-10 10kV DC output Increases DC output range to 10kV DC (with decreased current limits). DC-10 option does not affect AC output specs. DC-10 requires an external box with circuitry inside.
  • Page 44 The 944i is equipped with a fan to cool the internal electronic circuitry. Periodically it is advisable to inspect the filter assembly located on the rear panel. In areas where there is a high level of dust or other airborne particulate matter, the inspection of this filter should be conducted more often.

  • Page 45: Verification Procedure

    V LO terminal to the Common terminal. Select the VDC direct mode on the 944i and engage the output, but leave the unit running at 100 VDC. Select the proper resistor and connect it to the 944i (see table below). Edit the voltage up to 1kv, and take your readings.
  • Page 46 "LO Ω", "0", short leads then "Enter"). After the leads have been "nulled out", connect the leads to a calibrated 1 Ω resistor. The 944i should display 1.000 ±0.033 Ω. 944i Standard Unit and 944i DC-7 Calibration Data Table Measurement...
  • Page 47 1, 10 or 100 volts at a time using the up and down arrows. Adjust the voltage until the meter reads exactly 500 volts. Note: The display on the 944i will reflect the adjusted value not the value shown on the meter.
  • Page 48 THEN PRESS ENTER Remove all connections from the 944i except the short from V-LO to Chassis Sense. If no adjustment of the current measurement is needed, the current calibration portion of this procedure may be skipped by pressing CLR at this prompt. To continue, press enter.
  • Page 49 In the direct lo ohm mode zero out the test lead resistance before attaching leads to a 1 ohm standard resistor. The uncertainty of the 944i in this mode is 1 ohm +/-0.033. Should the reading fall near or outside of this tolerance adjustment may be needed.

  • Page 50: Eprom Upgrade Procedure

    Connect a known 5 ohm resistor to the 944i. Verify that the reading is within +/- 45 counts. If necessary adjust RV4 to bring reading within tolerance (typically 30 counts low). If any adjustment is required then go back to step 2 and repeat until both points are within tolerance.

  • Page 51: Specifications

    Specifications AC DIELECTRIC MODE AC Voltage Output: Voltage uncertainty is equal to the square root of the selected output. Examples: Output Formula Accuracy 100 VAC Sqrt(100) ± 10.0 VAC 500 VAC Sqrt(500) ± 22.4 VAC 1000 VAC Sqrt(1000) ± 31.6 VAC 5000 VAC Sqrt(5000) ±...
  • Page 52 Voltage uncertainty is equal to the square root of the selected output times 0.75 Examples: Output Formula Accuracy 100 VDC Sqrt(100) * 0.75 ± 7.5 VDC 500 VDC Sqrt(500) * 0.75 ± 16.8 VDC 1000 VDC Sqrt(1000) * 0.75 ± 23.7 VDC 5000 VDC Sqrt(5000) * 0.75 ±...
  • Page 53 Range Current Limit 100 to 500 VDC 20mA 500 to 4000 VDC 35mA 4000 to 4500 VDC 30mA 4500 to 5000 VDC 25mA 5,000 to 7,000 VDC* * Requires option DC-7 DC Current Limits with option DC-10: Range Current Limit 100 to 10,000 VDC 10mA HIGH RESISTANCE MODE...
  • Page 54 RS232C - 1200, 2400, 4800, 9600 Baud rate selectable Remote Interface Option "IF-4" Parallel - IBM/Centronics compatible VICL - Vitrek auxiliary unit control loop Stated specifications are bipolar and apply for one year within ± 5°C Accuracy from calibration temperature (20 to 25°C).

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