Model 6200B - Krohn-Hite

Model 6200B - Krohn-Hite
Model 6200B
10Hz TO 1MHz
DIGITAL PHASEMTER
SERIAL NO.________
OPERATING AND
MAINTENANCE MANUAL
Unit 4, 15 Jonathan Drive, Brockton, MA 02301-5566
Tel: (508) 580-1660; Fax: (508) 583-8989
E-mail: info@krohn-hite.com; Web: www.krohn-hite.com
Model 6200B
Table of Contents
TABLE OF CONTENTS
SECTION
1.0
2.0
3.0
4.0
5.0
6.0
PAGE
GENERAL DESCRIPTION ................................................................................. 1
OPERATION......................................................................................................
INCOMING INSPECTION ...................................................................................
CIRCUIT DESCRIPTION ....................................................................................
MAINTENANCE.................................................................................................
CALIBRATION ..................................................................................................
ILLUSTRATIONS
Figure
1
2
3
Page
Model 6200B Phasemeter ................................................................................. ii
Simplified Block Diagram .................................................................................
Test Points and Adjustable Components .........................................................
TABLE
Table
1
2
Page
Optional BCD Output Pin Connections.............................................................
Performance Check ..........................................................................................
i
ii
Model 6200B
Section 1 – General Description
SECTION 1
GENERAL DESCRIPTION
1.1
INTRODUCTION
The Krohn-Hite Model 6200B measures the difference in phase angle between two sine waves or two
square waves of coincident frequency, over a range of 10Hz to 1MHz, and provides a direct readout of
the phase angle, in degrees, with 0.1° resolution. The 6200 provides a basic accuracy of 0.5°, and
accepts input signal levels between 0.1 volts and 120 volts RMS. A 3-1/2 digit, planar gas discharge
display provides the direct readout of the phase angle for leading or lagging angles, between ±180.0°.
The 6200 is designed for virtual “hands-off” operation. The wide input voltage range provides a
continuous dynamic range of better than 60dB between the two input signals. The exceptional stability
of the 6200 (better than 0.2°/month) eliminates the need for daily readjustment of zero and full scale
calibration. An auto-sensing circuit in the 6200 determines the correct polarity sign to be displayed, for
lending or lagging angles.
Additional features of the Model 6200 include an analog output, equal to 10mV per degree of phase, for
use with an external meter or strip chart recorder, plus an optional BCD output.
The instrument is carefully inspected, aged and adjusted before shipment, and should be ready for
operation when it is unpacked. If it appears to have been damaged in shipment, make a claim with the
carrier and notify Krohn-Hite immediately.
1.2
SPECIFICATIONS
Frequency Range
10Hz to 1MHz.
Accuracy
Sine Waves: 0.5°, 10Hz to 1KHz; rising to 1° at 50kHz; 1.5°/50kHz above 50kHz.
Square Waves: 1.5°, 10Hz to 50kHz; 1.5°/50kHz above 50kHz.
Input Signal Amplitude
0.1 volts RMS to 120 volts RMS. (Derate accuracy specifications by a factor of 2 for input levels
between 0.1 volts and 1.0 volts RMS and between 20 volts and 120 volts RMS on either input).
Input Waveforms
Sine waves or square waves.
Input Impedance
Greater than 100k ohms in parallel with 50pf.
Maximum DC Component
±200 volts.
1
Section 1 – General Description
Model 6200B
Response
Time Constant: Approximately 1 second.
Settling Time (to within 1° of reading): Between 1 and 10 seconds, dependent upon change in input.
Display
0.55:, 7-segment, planar gas discharge. Continuous, -180.0° to +180.0°.
Resolution
0.1°
Repeatability
±1 digit
Drift
±0.2°/30 days
Temperature Coefficient
±0.03°/°C.
Ambient Temperature Range
0°C to 55°C.
Analog Output
(For use with an external meter or strip char recorder): 0 to +1.8 volts DC, 10mV/degree phase, 600
ohms output impedance. Separate +/- polarity output line to indicate leading or lagging phase.
+ angle: Voh = 2.4V, Isource = -1mA
- angle: VOL = 0.4V, Isink = 20mA
BCD Output (Optional)
Provides 13 lines of parallel BCD output, equivalent to phase angle reading, plus 1 polarity output and 4
separate 3-state control lines. Compatible with DTL, RTL and TTL logic.
(May be externally connected for serial operations; all output lines are 3-state, i.e. “high”, “low” and
“high Z” to permit serial, multiplex, etc. operation. Consult Factory for details).
BCD and +/- Output Levels:
Voh = 2.5V, Isource = -4.2mA
Vol = 0.4V, Isink = 2.1mA
3-State Output Leakage Current
±7.5 uAdc, max.
Disable Input Levels:
Voh > 3.5V
; R load = 47K ohms
Vol > 1.5V
2
Model 6200B
Section 1 – General Description
Terminals
Front Panel: REF (BNC), SIG (BNC).
Rear Panel: REF (BNC), SIG (BNC), AC power receptacle.
Power Requirements
105-125 volts, or 210-250 volts, single phase, 50-60 Hz, 10 watts.
Dimensions and Weights
3-1/2” high, 8-5/8” wide, 11” deep, 6 lbs./3 kgs net, 8 lbs./4 kgs shipping.
Specifications apply at 25°C, ±5°C unless otherwise noted.
Optional Rack-Mounting Kit
Part No. RK-38; permits installation of 6200 into a standard 19” rack spacing.
Specifications are subject to change without notice.
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Section 1 – General Description
Model 6200B
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4
Model 6200B
Section 2 – Operation
SECTION 2
OPERATION
2.1
POWER REQUIREMENTS
The Model 6200 may be used with either a 105-125 volt, 50-60Hz AC line, or a 21-250 volt, 50-60Hz
AC line. A rear panel LINE switch selects the proper mode of operation. When the line voltage is 115
volts, a 1/8 ampere slow blow fuse is required; when the line voltage is 230 volts, a 1/16 ampere fuse
must be used. A detachable, 3-wire line cord is provided with the unit.
2.2
OPERATION
To operate the 6200 Phasemeter, first make the appropriate power connections outline in the previous
section, and push the POWER switch on the ON (recessed) position; allow the instrument to warm up
for at least 30 minutes to obtain rated accuracy.
Connect the reference signal to the Phasemeter’s REF input; connect the unknown phase to the SIG
input. (The use of two similar length cables is recommended to avoid errors due to stray capacitance,
particularly at high frequencies). The phase angle between the two inputs, in degrees, will be displayed
by the front panel Digital Panel Meter. Additional phase measurements can be made by simply
observing the meter display.
NOTE: The 6200 displays the phase angle by which the SIG input leads or lags the REF input, as
determined by the display’s polarity indicator.
The 6200 covers a phase measurement range of –180.0° to +180.0° and will automatically shift the
reading by 360.0° if the phase angle exceeds the full scale range in either direction. For example, if the
phase angle being measured exceeds +180.0°, say +200.0°, it will be shifted 360.0° so that the meter
will now read –160.0°. The meter display allows approximately 5° overrange before it shifts the
reading.
The accuracy specifications of the 6200 are outlined in Section 1.2, and apply for two sine wave or two
square wave inputs, with amplitudes between 1.0 and 20 volts RMS. The accuracy specification must
be derated a factor of 2 if the input voltage on either channel falls above or below the 1-20 volt range.
The Phasemeter accuracy will also be affected if a sine wave is used for one input, while a square
wave is used on the other. The exact error produced in this case cannot be predicted; an estimate
would be in the order of 1 to 3 degrees.
2.3
ADDITIONAL SOURCES OF ERRORS
2.3.1
Input Signal Distortion
Typically, any effects due to input signal distortion will be minimal; however, if the peak of the
distortion occurs at the crossover point of one or both of the input waveforms, the worst case
error may be approximately ±0.6° per 1% distortion. Similar distortion on both inputs, however,
will tend to cancel the error.
5
Section 2 – Operation
2.4
Model 6200B
2.3.2
Random Noise
Another source of phase error is caused by random, or broadband noise present on either or
both input waveforms. Typically, an error of 0.1° can occur for a signal to noise ratio of 30:1 on
both input signals. (Noise bandwidth: 500kHz; input frequency: 10kHz).
2.3.3
Non Symmetrical Square Waves
Typical errors produced by variations in the symmetry of the two input waveforms will generally
be proportional to the percentage of variation.
ANALOG OUTPUT
The analog output provides a positive DC voltage equal to 10mV per degree of phase displayed, and
may be used with an external meter or strip-chart recorder. The analog output is located on the rear
panel. Output impedance is 600 ohms.
A separate output marked “±” provides a TTL output level that indicates whether the polarity of the
display is plus or minus. The output goes “high” (~2.4V) for positive angles, and “low” (~0.4V) for
negative angles.
2.5
BCD OUTPUT (OPTIONAL)
This option provides an equivalent BCD output of the front panel display, plus 5 additional control lines
and a programming ground return. The logic levels are compatible with DTL, RTL and TTL logic.
Each digit of the display, with the exception of the 100’s digit, is represented by 4 data output lines
coded in a 1-2-4-8 format (pins 4-15); the 100’s digit is represented by a single output line (pin 3).
The polarity (+/-) output line (pin 1) indicates when the polarity sign of the display is plus or minus; the
output logic level remains “high” for positive angles and switches to its “low” state for negative angles.
The 4 remaining control lines, labeled “3-state control” (pins J, K, L, and M) provide a disable function
for each digit. The “3-state control” refers to the 3 possible states of the data output lines. When the
control lines are left “low” or open-circuit, the digits will be enabled; all data output lines will be “high” or
”low” depending on the digits displayed. The source impedance of the output lines is low during the
enable state. When the control lines are pulled “high” transfer of data will be inhibited; all output lines
disabled will be at zero output level and exhibit a high source impedance. The advantage of this “3state control” is that is allows the user to externally reconnect the data output lines for serial or multiplex
operation, without the need for additional buffer stages.
6
Model 6200B
Section 2 – Operation
Table 1 provides the programming pin connections for this option. A programming edge connector,
TRW type 251-15-30-160 is also provided.
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
J
K
L
M
S
Function
+/N/C
100.0
080.0
040.0
020.0
010.0
008.0
004.0
002.0
001.0
000.8
000.4
000.2
000.1
100’s 3-state control
10’s 3-state control
1’s 3-state control
0.1’s 3-state control
GND
Description
“high” for pos. angle
“low” for neg. angle
Phase angle
BCD outputs
“high” for “high Z”
“low” or open-circuit
for enable
programming ground
Programming edge connector, TRW type 251-15-30-160 is provided.
7
Section 2 – Operation
Model 6200B
This Page Intentionally Left Blank.
8
Model 6200B
Section 3 – Incoming Inspection and Checkout
SECTION 3
INCOMING INSPECTION AND CHECKOUT
3.1
INTRODUCTION
The following procedure is used to verify that the phasemeter is operating within specifications, both for
incoming inspection and for routine servicing. Tests should be made with all covers in place, and the
procedure below should be followed in sequence.
3.2
TEST EQUIPMENT REQUIRED
a)
Precision Phase Standard or phase generator, that will provide two sine wave or two square
wave signals with adjustable phase from zero to ±180°, with better than 0.1° accuracy from
10Hz to 10kHz (Dytronics Models 311/RT-717S, 312, 410 or equivalent).
or,
Variable phase sine/square generator, adjustable from zero to ±180°, for frequencies between
10Hz to 50kHz, with sine wave distortion no greater than 0.1% (Hewlett-Packard Model 203A or
equivalent), plus a precision digital phasemeter with at least 0.1° accuracy from 10Hz to 50kHz,
for accurately setting the phase output of the generator (Krohn-Hite Model 6600 or equivalent).
b)
3.3
High impedance AC voltmeter, zero to at least 10 volts RMS.
PROCEDURE
Before operating the phasemeter, refer to Section 2.1, Power Requirements, for the appropriate AC line
voltage and fuse required. Connect the phasemeter’s line cord to the AC power source and push the
POWER switch to the ON (recessed) position; allow the unit to warm up for a few minutes before
beginning the procedure.
Connect the outputs of the Phase Angle Source to the 6200 respective inputs. The reference signal is
connected to the 6200 REF input; the unknown phase is connected to the SIG input.
The 6200 displays the phase angle by which the SIG input leads the REF input.
Refer to Section 1.2, Specifications when performing accuracy checks. Table 2 is provided to simplify
the accuracy test.
9
Section 3 – Incoming Inspection and Checkout
Model 6200B
TABLE 2. Performance Check
3.4
Phase
Angle Range
-180.0° to
+180.0°
REF & SIG Input
Voltage Range
1-10V RMS
Frequency
Range
10Hz-10kHz
10kHz-50kHz
50kHz
Specifications
Sine
Square
0.5°
1.5°
1.0°
1.5°
1.5°/
1.5°/
50kHz
50kHz
-180.0° to
+180.0°
0.1-1.0V RMS or
10-120V RMS
10Hz-1MHz
derate above
specifications
by a factor of 2
ANALOG OUTPUT CHECK
The analog output is a positive DC voltage equal to 10mV per degree of phase angle displayed. The
check the analog output, connect the DCVM to the rear panel terminal marked “<” the output should be
approximately 10mV times the absolute value of the displayed reading.
The polarity output is a TTL logic level that indicates when the reading is plus (+) or minus (-). Connect
the DCVM to the rear panel terminal marked “+/-“; a logical “1” (2.4V) indicates a plus or leading angle,
while a logical “0” (0.4V) indicates a minus or lagging angle.
3.5
OPTIONAL BCD OUTPUT CHECK
To check the optional BCD output, connect the phase generator to the respective phasemeter inputs;
adjust the phase generator to obtain the readings found in Table 1, page 6, and measure the logic level
of each data output line for each reading in the table. A logical “1” is approximately 2.4V and a logical
“0” is approximately 0.4V. Be sure to connect the common of the DCVM to the BCD output digital
ground (pin S).
The +/- polarity indicator (pin 1) provides a logical “1” (2.4V) for plus or leading phase angle readings,
and a logical “0” (0.4V) for minus or lagging readings.
NOTE: This output should not be confused with the +/- polarity output provided for the analog output.
10
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