MODEL 3000
DIGITAL CAPACITANCE
METER
Operation and Calibration Manual
Serial Numbers
This manual applies directly
to instruments with serial numbers 30700 and up, and with A0 mainboard PCB assembly
8503000-0-3.x.
Rev. 3.x, 25 May 2020
Copyright 2020
Serial Number: ___________
For technical assistance, contact
GLK INSTRUMENTS
Email: support@glkinst.com
Website: www.glkinst.com
TABLE OF CONTENTS
|
Section |
|
Page |
|
|
|
|
|
I. Warranty |
|
3 |
|
|
|
|
|
II.
Product Use Restrictions |
|
3 |
|
|
|
|
|
III.
Return Material Authorization |
|
3 |
|
|
|
|
|
IV.
Specifications |
|
4 |
|
|
|
|
|
V.
Description |
|
5 |
|
|
|
|
|
VI.
Initial Preparation |
|
7 |
|
|
|
|
|
VII.
Operating Instructions |
|
8 |
|
|
|
|
|
VIII.
Servicing Information |
|
12 |
|
|
|
|
|
IX.
Calibration |
|
14 |
|
|
|
|
|
X.
Revisions |
|
15 |
|
|
|
|
|
XI.
Options |
|
15 |
|
|
|
|
|
|
|
|
|
|
|
|
I. WARRANTY
GLK Instruments products are warranted against defects in workmanship and materials under normal use and service for one year from date of their shipment by GLK Instruments, except that components obtained from others are warranted only to the extent of the original manufacturers' warranties, if any. This warranty does not extend to any products that have been repaired or altered by others. GLK Instruments' sole liability and the Purchaser's sole remedy under this warranty are limited to repairing or replacing defective products. The repair or replacement of defective products does not extend the warranty period. This warranty does not apply to components or products which by the nature of the applications are consumed in operation or which have a normal life inherently shorter than one year. Examples of this are batteries, components or products exposed to nuclear radiation, or used in the measurement of detection of explosions. GLK Instruments shall not be liable for consequential damages under any circumstances.
THE FOREGOING WARRANTY AND REMEDY ARE IN LIEU OF ALL OTHER REMEDIES AND ALL OTHER WARRANTIES, WRITTEN OR ORAL, STATUTORY, EXPRESS, OR IMPLIED, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
II. PRODUCT USE
RESTRICTIONS
GLK Instruments does not
recommend the use of any of its products or the incorporation of any of its
products by second parties in their products in (a) life support applications
where failure or malfunction of the product can be reasonably expected to cause
failure of the life support device or to significantly affect its safety or
effectiveness, (b) any nuclear facility applications which including nuclear
reactors and devices designed or used in connection with the handling, processing
packaging, preparation, utilization, fabricating, alloying, storing, or
disposal of fissionable material or waste products, (c) consumer applications
where failure or malfunction of the product can be reasonably expected to cause
injury, and (d) applications where failure or malfunction of the product can
reasonably be expected to place the health and safety of the general public in
jeopardy. GLK Instruments will not knowingly sell its products for use in such
applications unless GLK Instruments receives in writing satisfactory assurances
that (a) the risks of injury or damage have been minimized, (b) the customer
assumes all such risks, and (c) the liability of GLK Instruments is adequately
protected under the circumstances.
III. RETURN MATERIAL AUTHORIZATION
In the unlikely event that any
of the products of GLK Instruments need repair, contact GLK Instruments for
a return material authorization (RMA) number.
IV. SPECIFICATIONS
(25 oC unless specified otherwise)
Electrical |
|
|
|
Capacitance range: |
|
2.000 pF to 200.0 nF |
|
Resolution: |
|
0.001 pF to 0.1 nF |
|
Display: |
|
3 1/2 digit liquid
crystal display (LCD) |
|
Accuracy with or
without probes: |
|
± (0.1% of reading + 2 digits) |
|
Measurement
frequencies: |
|
24 kHz (2 pF, 20 pF, 200 pF, 2 nF) |
|
|
|
2.4 kHz (20 nF) |
|
|
|
240 Hz (200 nF) |
|
Charging voltage: |
|
5 V (all ranges) |
|
Offset adjustment: |
|
1.5 pF |
|
Analog output
voltage(1): |
|
0-200 mV (unbuffered) 0-200 mV, 0-2 V, 0-5 V (buffered, option
002) |
|
Analog bandwidth(2)
: |
|
1.2 Hz (2 pF), 2.8 Hz (20 pF), 15 Hz (200
pF), 64 Hz (2 nF, 20 nF, 200 nF) |
|
Source resistance: |
|
1000 ohms (1%) |
|
Reference
output voltage: |
|
5.000 V DC |
|
Source resistance: |
|
1000 ohms (1%) |
|
Digital I/O: |
|
USB Port 1.1 compliant, optically isolated |
|
Battery: |
|
9 V alkaline (NEDA 1604A) |
|
Auxiliary power: |
|
12 - 14 V DC, 50 mA supply
|
|
|
|
with 2.1 mm DC power jack |
|
USB port power: |
|
Isolated, 4.5V to 5.5V, 300mA |
Environmental |
|
|
|
Operating
Temperature: |
|
0 oC to +50 oC |
|
Storage
Temperature: |
|
-20 oC to +70 oC |
|
Operating relative
humidity: |
|
80% (noncondensing) |
Mechanical |
|
|
|
Package: |
|
Bench top, portable instrument case |
|
|
|
with tilt bail |
|
Dimensions: |
|
8.50 x 9.52 x2.44 inches |
|
Net Weight: |
|
3 lbs |
Accessories Supplied |
|
|
|
Two miniature shielded probes and probe
accessories (PN 2110112) 9 V battery (NEDA 1604A) Operation and Calibration Manual 100 nF Chip Capacitor Battery eliminator (PN 4001200): input 120
VAC, 60 Hz, 6 W; output 9 VDC, 200 mA; 2.1 mm Plug Application DVD and USB cable Optional Accessories
International battery eliminator (PN 4001201): input 90 to 264 VAC, 47 to 63 Hz, 18 W, IEC 320 connector; output 12 VDC, 1.5 A, 2.1 mm Plug. Customer supplies AC cord set, 3-prong IEC 320 to local connection. (1) Note: Analog
output voltages for Option 002, Buffered Analog Output Option, are 0–200 mV,
0-2 V, and 0–5 V, jumper selectable. Option 002 default jumper setting is 0-2
V. (2) Note: Wideband Option
001 increases bandwidth to ~70 Hz on each range. No additional charge for
this option if specified at time of order. Bandwidth of each range can be
customized at time order. |
||
V. DESCRIPTION
The Model 3000 Digital Capacitance Meter is the first commercially available low cost, high accuracy instrument designed exclusively for the measurement of very small value capacitors and capacitors whose size and shape are not conveniently handled by conventional sockets, clamp fixtures, or alligator clip leads. This instrument is particularly useful for the measurement chip capacitors whose small size precludes the use of identifying marks.
The Model 3000 employs a unique and patented (U.S. Patent No. 4806846) switched capacitor circuit and a ratio metric measurement technique that eliminates errors due to stray capacitance to ground. The patented circuit has high common-mode rejection and eliminates errors due to changes in the reference voltage from temperature, aging, etc. This unique circuit allows the capacitor under measurement to be remotely connected to the meter via two, miniature, shielded probes or coaxial cables without affecting the accuracy or resolution of the instrument.
The
convenience of using miniature probes solves the costly problem of constructing
special test fixtures and shielded boxes for the determination of the
capacitance of a variety of objects. For example, the Model 3000 with its
standard probes can easily determine the capacitance between the pins of a
connector, the large signal gate capacitance of power MOSFETs, the depletion
capacitance of diodes, the capacitance between the traces on a printed circuit
board, or even the static capacitance of microstrip or stripline microwave
circuits. Using ultra-miniature, shielded probes, very accurate wafer level,
large signal measurements of MOS capacitors are easily obtained.
Miniature,
shielded probes are normally supplied with the instrument; however, the Model 3000,
due to its unique circuitry, can accommodate a large variety of custom built
shielded probes, special shielded connectors, or test fixtures. Coarse and fine
offset adjustment potentiometers are provided on the front panel of the
instrument to compensate for any unshielded test fixture capacitance up to 1.5
pF. Capacitors can be remotely connected to the Model 3000 using standard
coaxial cables such as RG-223. The Model
3000 maintains its accuracy and resolution with or without probes.
Auxiliary
analog outputs of the LCD meter reading (0-200mV) and reference (charging)
voltage (5.00 V) are available on the back panel. These outputs can be
connected to digital voltmeters, data loggers, computer data acquisition
systems, etc. using standard banana jacks and shielded cables. Option 002,
Buffered Analog Output, provides additional gain to scale the LCD meter reading
by 1X, 10X, and 25X, or 0-200 mV, 0-2 V, and 0-5 V, respectively.
Fully
isolated digital I/O is available at the USB port on all new instruments
starting at serial numbers 30024 and up. Older instruments can be upgraded to
support digital I/O for a nominal charge. Contact GLK Instruments for
details. The USB port provides access to
the instrument’s 24-bit ADC and range switches. Digital I/O support extends the resolution
and range of the instrument as shown in Table I.
A
standard 9 V alkaline or lithium battery powers the Model 3000. Battery life is
approximately 200 hours. An auxiliary DC
power jack is provided for powering the instrument from the battery eliminator
(US version PN 4001200 or optional, international version PN 4001201). The USB port can also supply isolated power to
the Model 3000. The USB cable must be connected to a compliant USB port
(powered port) on the host computer. When powered by the USB port, the Model
3000 is always on, independent of the ON/OFF switch position. Due to the optical and magnetic isolation of
the USB port from the Model 3000 circuitry, the USB port is active only when
powered from the host computer.
Table
I. Extended Range and Resolution at USB Port
|
Front
Panel |
USB
Port |
||
|
Range Switch |
3
˝ Digit LCD Meter |
Extended Range |
Extended Resolution |
|
2
pF |
1.999
pF |
3.0000
pF |
0.1
fF |
|
20
pF |
19.99
pF |
30.000
pF |
1
fF |
|
200
pF |
199.9
pF |
300.00
pF |
10
fF |
|
2
nF |
1.999
nF |
3.0000
nF |
0.1
pF |
|
20
nF |
19.99
nF |
30.000
nF |
1
pF |
|
200
nF |
199.9
nF |
300.00
nF |
10
pF |
VI. INITIAL
PREPARATION
The Model 3000 (PN 2903000-0) is supplied ready for use with a battery, battery eliminator, two probes with accessories, USB cable, and application CD with USB port drivers and LabVIEW demonstration programs. If a 9 V battery is not installed, open the battery compartment cover on the back of the instrument by removing the two thumbscrews. Connect a 9 V battery to the polarized snap lead, clamp the battery to the cover, replace cover, and secure with thumb screws. If the instrument is to be stored for an extended period, remove the battery to prevent damage from leakage.
*********************************************************
ALWAYS DISCONNECT THE BATTERY ELIMINATOR AND
ANY TEST FIXTURES OR PROBES FROM THE INSTRUMENT WHEN REPLACING THE
BATTERY. BEWARE OF STATIC ELECTRICITY
*********************************************************
The
instrument is now ready for use; however, it is recommended to perform the
following initial checkout to become more familiar with the instrument. Select
the 2.000 pF range by depressing the respective front panel switch. Turn on the
instrument by pressing the ON switch. The liquid crystal display should appear
and settle to a stable reading of ± 0.002 within a few seconds. The instrument
was adjusted at the factory to read ± 0.002
pF. If the display is not within ± 0.002 pF, then adjust the “OFFSET ADJ COARSE
FINE” potentiometers on the front panel of the instrument. Unpack the two
probes, and connect each probe to the front panel BNC connectors. Hold probes
at least 6 inches apart and observe the display. The display should read ±
0.002 pF provided the probes are held stationary. If necessary, adjust the
OFFSET FINE potentiometer to zero the display. Hold the probes tips about 1/10
inch apart. You should observe a reading of approximately 0.015 pF or 15
femtofarads. Place the probes at least 6 inches apart again and check the zero
on the other ranges by depressing each range switch while observing the
display. Next, measure a 100 nF chip capacitor
supplied with the unit. First select the 200 nF range;
second touch each of the metalized ends of the chip capacitor with the probe
tips; and third, read the display. The 100 nF chip
capacitor has tolerance of ± 20%.
*******************************************************
CAUTION - ALWAYS DISCHARGE HIGH VOLTAGE
CAPACITORS BEFORE MEASURING TO AVOID DAMAGE TO INSTRUMENT
*******************************************************
You should now be familiar with the general use of the Model 3000 Digital Capacitance Meter. For a more detailed discussion of the operation of the Model 3000, refer to the following section.
VII. OPERATING INSTRUCTIONS
A detailed description of each function of the instrument is given in this section. The basic functions of the Model 3000 are listed below.
Front Panel:
1)
Display, 3 1/2 digit LCD
2)
Range switch, 2 pF to 200 nF, push-to-select
3)
Power switch, push-ON, push-OFF
4)
Cx HIGH input
BNC (positive connection, drive)
5)
Cx LOW input
BNC (negative connection, sense)
6)
OFFSET ADJ COARSE FINE potentiometers
Rear panel:
7)
9 V battery compartment
8)
Auxiliary DC power jack
9)
Analog output jacks, 0-200 mV (Option 002, 0-200 mV, 0-2 V or 0-5 V)
10)
Reference voltage output jacks, 5.00 V DC
11)
USB port
1) The
display is a self-contained 3 1/2 digit LCD digital voltmeter with polarity and
decimal point indication. The decimal point
is automatically selected when the desired range switch is pushed.
2) The
range switch is a push-to-select interlocking assembly. Ranges are 2 pF, 20 pF,
200 pF, 2 nF, 20 nF, and 200 nF. A resolution of 0.001
pF or 1 femofarad can be achieved on the 2 pF range.
3) The
power switch is a push-ON and push-OFF type. Note: when powered by the USB
port, the Model 3000 is always on independent of the ON/OFF switch position.
4 & 5) Connection to the Model 3000 is via the
BNC's on the front panel. Normally the probes supplied with the instrument will
be connected to these terminals. However, custom-built shielded probes,
connectors, or other special test fixtures can be connected to these terminals
without affecting the accuracy of the instrument. The terminal marked (+) or
HIGH is the positive drive or charging terminal and should be connected to the
positive terminal of polarized capacitors. Likewise, the negative sense
terminal (-) or LOW input should be connected to the negative terminal of
polarized capacitors. The HIGH terminal should always be connected to the outer
foil, plate, or larger electrode of the capacitor under measurement and the LOW
terminal to its other electrode to minimize noise pickup. In the case of
3-terminal capacitors, such as calibration standards, the shield of the
capacitor (i.e. its third electrode) should be connected to the ground shield of
the probes. An alternative is to connect a 3-terminal capacitor to the
instrument using coaxial cables. In electrically noisy environments the
capacitor under test may require shielding to obtain a stable reading. To
maintain accuracy and obtain low noise readings, connect external shielding to
both probe shields.
The Model 3000 uses a combination of CMOS and JFET devices to charge and discharge the capacitor under test; consequently, voltage transients can damage these devices and will cause the instrument to malfunction. All capacitors, but specifically high voltage and high capacitance capacitors, must be discharged first before measurement to avoid damage to the instrument.
**********************************************************
DISCHARGE ALL CAPACITORS BEFORE MEASUREMENT
TO PREVENT DAMAGE TO THE INSTRUMENT AND TO PREVENT PERSONAL INJURY
**********************************************************
The drive level that is presented to the capacitor under test from the (+) or HIGH connection is +5.00 V peak with respect to the (-) or LOW connection or to ground (shields); thus, a wide range of capacitors that have breakdown voltages as low as 5 V can be measured with the Model 3000 without damaging the capacitor under test. Avoid capacitors that have leaky dielectric or high conductance. The Model 3000 cannot measure conductance. Depending on the range, leaky dielectric capacitors can produce erroneous readings. Likewise, the depletion capacitance of diodes must be measured under reverse bias conditions, i.e. HIGH terminal is connected to the cathode, and the LOW terminal is connected to the anode to reverse bias the diode.
6) The “OFFSET
ADJ COARSE FINE” potentiometers on the front panel of the instrument are used
primarily to compensate for the capacitance between the unshielded terminals of
test fixtures used to measure axial and radial leaded capacitors. The OFFSET
potentiometers can subtract up to 1.5 pF of test fixture capacitance. The
OFFSET potentiometers are used also to zero the instrument on the 2 pF scale
and may be required occasionally due to amplifier drift, component replacement,
or operation at elevated temperatures.
7) A 9 V battery is housed in a compartment on the
rear of the instrument. The Model 3000 will operate for approximately 200 hours
on a 9 V alkaline battery. A low dropout voltage regulator allows extended use
of the battery down to a voltage of about 6.2 V before replacement.
8) The
auxiliary DC power jack provides the capability of operating the instrument
continuously from an external power source such as the battery eliminator (PN
4001200). The internal 9 V battery is automatically disconnected from the instrument
when the battery eliminator is connected.
9) The
analog output jacks provide a 0-200 mV DC signal proportional to the capacitor
value under test. Option 002, Buffered Analog Output, provides additional gain
to scale the LCD meter reading by 1X, 10X, and 25X, or 0-200 mV, 0-2 V, and 0-5
V, respectively.
The bandwidth of the analog output signal is
range dependent as shown in Table II. The source resistance of the analog
output is 1000 ohms.
Table II. Analog
Bandwidth
|
Range |
Measurement Frequency
(Hz) |
Bandwidth (Hz) (Standard) |
Bandwidth (Hz) (Option 001) |
|
2 pF |
24,000 |
1.2 |
67 |
|
20 pF |
24,000 |
2.8 |
71 |
|
200 pF |
24,000 |
15 |
78 |
|
2 nF |
24,000 |
64 |
79 |
|
20 nF |
2400 |
64 |
79 |
|
200 nF |
240 |
64 |
79 |
10) The instrument's internal 5 V DC
reference voltage is available at
the reference output jacks. Its source resistance is 1000 ohms. The reference
output voltage is used to provide external ratio metric capability to remove
errors in the analog output signal due to changes in the reference voltage from
temperature and long term drift. For ratio metric measurements, connect the 5 V
reference output to the external reference input on digital voltmeters, data
loggers, etc. that provide for this option. Alternatively, errors from
variations in the reference voltage can be removed from the analog output
signal by calculating the ratio of analog output to the 5 V reference output
and multiplying by the appropriate scale factor. Using the external outputs of
the Model 3000 with precision digital voltmeters or data acquisition systems,
capacitors can be measured to greater precision and to a resolution of approximately
10 ppm (range and bandwidth dependent).
11) USB port provides fully isolated digital I/O and
power, extended resolution and range as shown in Table I, and powers the Model
3000 from the host computer. To access the USB port, the appropriate drivers
must be installed on the host computer. The drivers are available on the
application DVD-ROM or can be down loaded from our website: www.glkinst.com/cmetersoftware.
To install the USB drivers on the host computer, follow the instructions in the
file: ReadmeUSBDriverInstall
To demonstrate the basic
features of the Model 3000 digital I/O, load and run the LabVIEW® demonstration
program. This program is available as a standalone application or VI. The
demonstration programs are written for various versions of LabVIEW® and
complied with National Instruments' (www.ni.com)
Application Builder. Users without LabVIEW® can run the application by
installing the LabVIEW® runtime engines included on the Model 3000 application DVD-ROM.
Note: All software and drivers
for the Model 3000 have been tested only on computers running Microsoft's
Windows XP®, Windows 7®, and Windows 10®. To completely install all USB
drivers, “found new hardware” may run four times in Windows XP®. All of the
Model 3000 and USB communication VI's were written initially in LabVIEW® 7 and
been verified for later versions of LabVIEW®. The software will probably fail
to run in versions of earlier than LabVIEW® 7. Contact National Instruments, www.ni.com, to upgrade to version 7 or later; or
install the appropriate version of the LabVIEW® run time engine and run the
executable version of the demonstration program.
VIII. SERVICING INFORMATION
For service and calibration of the Model 3000 Digital Capacitance Meter, contact GLK Instruments directly. Complete repair and calibration services are maintained by GLK Instruments; however, minor repair and calibration can generally be performed in the field if you have access to a precision 3-terminal capacitor standard. Location of parts, test points, and adjustments are shown in Figure 1.
The capacitor measuring technique in the Model 3000 uses a switched capacitor circuit consisting of two JFET transistors driven by CMOS logic and a convert current to voltage circuit with low pass filter. Input protection from voltage transients is built-in to the switched capacitor circuit; however, failure to discharge high voltage capacitors or static discharge can damage the circuitry. The switched capacitor circuit includes these replaceable parts Q3 and Q4 (2N5116 JFETS), U3, U4, and U6 (4049 CMOS hex buffers), and U10 (TL061 opamp).
In the event that the switched capacitor circuit is damaged, spare parts are located inside the Model 3000 on the main board, A0, below the ADC-digital I/O board (USB interface), A3, if present. The spare parts include 2-each, 2N5116 JEFTS (Q3 and Q4), 2-each 4049 CMOS hex buffers (U3, U4, or U6), 1-each TL061 opamp (U10), and 1-each 0.125 A fuse (F1) for the external power supply or battery eliminator. All critical parts are socketed for easy replacement. JFETS, Q3 and Q4, should be replaced in pairs.
Basic
Diagnostics:
If the Model 3000 fails to power on under battery power, replace the 9 V battery through the compartment on the back of the instrument. Remove the two thumbscrews to gain access to the battery. If the Model 3000 fails to power up when connected to the battery eliminator but operates normally on battery power, check the battery eliminator for approximately 12 V between the center pin and outer conductor and fuse, F1. Replace battery eliminator if defective. To check fuse, open the Model 3000 by removing the four screws on bottom of the instrument and remove the top cover. Check fuse with an ohmmeter and replace if open using the spare fuse. If the Model 3000 still fails to power on, contact GLK Instruments.
If you suspect that the input circuitry is damaged, first check regulated power supply voltage between A0TP2 and GND for a voltage of 5.000 ± 0.005 V. Check the negative supply voltage between A0TP4 and GND for a reading of -4.8 ± 0.5 V. If proper readings are obtained, proceed to the next step. Check that a 0 to 5 V square wave is present at the “HIGH” BNC terminal on the front panel. If there is no signal, replace U3 and U4; recheck for square wave. JFETS, Q3 and Q4, are located inside the rectangular metal shield. To gain access to Q3 and Q4, remove the two, 2-56 nuts on the top of the metal shield. Replace both Q3 and Q4, and zero the LCD meter using the coarse and fine adjustments. If unable to zero, replace U10 adjacent to Q3 and Q4. Repeat zero adjustment. Attach a 1 nF standard capacitor (P/N 2901409-102), and note the LCD reading. If the reading is 1.00 ± 0.02 nF, the Model 3000 is working correctly. Replace the metal shield and calibrate instrument. If the above repair is unsuccessful, the instrument will need factory service. Contact GLK Instruments for RMA and shipping instructions.
Figure 1. Location of parts, test
points, and adjustments. Spares
are located on the mainboard A0 near the battery. If the USB interface board A3
is installed, remove 5 screws and lift A3 out of the way to gain access to the
spares.
IX. CALIBRATION
Field calibration of the Model 3000 Digital Capacitance Meter can be accomplished using only a single 1.000 nF (1000 pF), 3-terminal standard capacitor such as General Radio or IET Labs (www.ietlabs.com) Model 1404-A standard reference capacitor. Refer to main circuit board, A0, and ADC-digital I/O board (USB interface), A3, for the location of test points and calibration adjustments. Adjustments and test points are labeled on the printed circuit boards (see Figure 1).
To calibrate the Model 3000, first remove the top half of the instrument case by removing the four screws located in the bottom half of the case. If operating in battery mode, check the battery voltage at A0TP1. If its voltage is below 7 V, replace the battery with a fresh 9 V alkaline or lithium cell. The Model 3000 should function correctly down to a battery voltage of approximately 6.2 V. Note, in the following procedure, the calibration standard is assumed to 1.0000 nF ± 0.0001 nF. Your standard may differ slightly in value; in that case, adjust the Model 3000 meter reading to agree with your standard.
Turn on the
instrument, measure the voltage at A0TP2, and adjust the 5 V potentiometer,
A0R5, to set the voltage at A0TP2 to +5.000 ± 0.005 V. Select the 2.000 pF
range and adjust the OFFSET COARSE and FINE potentiometers to zero the display.
The display should read ± 0.000 pF after zero adjustment. Select the 2.000 nF range and connect the 1.000 nF (1000 pF) standard
capacitor to the instrument using coaxial cables. Adjust the CAL potentiometer,
A0R11, for a display reading of 1.000 nF ± 0.000 nF.
Connect a
calibrated, high impedance voltmeter, such as the Agilent 34401A, to the ANALOG
OUTPUT terminals on the back of the instrument. The 34401A should be set as
follows: range to 200 mV, resolution to fast 6-digit, and input resistance to
>10 Gohm. Adjust the AUX CAL potentiometer, A0R27, for a reading of 0.1000 V
± 0.0001 V. If option 002, Buffered Analog Output, is installed and is set to 2
V (default) or 5 V output range, adjust A0R27 for a reading of 1.000 ± 0.001 V
or 2.500 ± 0.003 V, respectively.
Connect the
Model 3000 USB port to the host computer and run the Model 3000 LabVIEW®
demonstration program. Adjust AD CAL potentiometer, A3R7, for a software
display reading of 1.0000 nF ± 0.0001 nF. A3R7 is
located on the USB interface board in the approximate position shown in
Figure1.
This completes
the basic calibration of the instrument. All of the other ranges will track the
calibration on the 2.000 nF range to within ± (0.1% of
reading + 2 digits). Remove the standard capacitor and replace the cover. The
Model 3000 is now ready for use as precision capacitance meter.
X. REVISIONS
The
following changes are effective for instruments with serial numbers 30000 and
up (PCB Assembly 8503000-0-3 Rev 3 and up).
The 5 V
adjustment (A0R5) has been eliminated on instruments beginning with serial
number 31714 through 31725 and with PCB assembly 853000-0-3.3, 853000-0-3.5,
and 853000-0-3.6.
This
manual and any future revisions will be posted on our website: www.glkinst.com
XI. OPTIONS
Option
001 Wideband Analog Output
Wideband Analog
Output Option 001 increases the instrument’s bandwidth at the Analog Output terminals
to approximately 70 Hz on each range. The bandwidth of the instrument is determined
primarily by the values of the capacitors on Gain & Filter board A1 shown
in Figure 2 and by components on the A0 mainboard. To achieve full bandwidth offered by Option
001, the option needs to be requested at time of order. It is not a field
installable option. To install Option 001 in instruments that shipped with the
standard bandwidth board A1, the instrument must be returned to GLK Instruments to make the necessary
component changes on the A0 mainboard and to re-calibrate the instrument. The
bandwidth can be customized if full 70 Hz is not required by replacement of the
Gain & Filter board A1 only. Contact GLK Instruments for
details.
Figure
2. Gain &
Filter board A1. The location of the 4-40 screw holes used to secure it to the
A0 mainboard are shown on the left and right side of the board.
Option 002 Buffered Analog Output
The analog
output banana jacks provide an unbuffered 0-200 mV DC signal proportional to
the capacitor value under test. Option 002 inserts an adjustable gain stage in
the signal path between the unbuffered output and the banana jacks on the back
of the instrument. The gain is jumper selectable and can be set to scale the
LCD meter reading by 1X, 10X, and 25X, or 0-200 mV, 0-2 V, and 0-5 V,
respectively. Unless specified otherwise, the default setting is 10X or 0-2V
output range as shown in Figure 3.
NOTE: Option 002 is not a field installable. Contact GLK Instruments for details.
