Fluke - 7250A - Counter
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Equipment:
7250A
Date:
1978
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Information
1-2. The Model 7250A is a Universal Counter Timer capable of
measurements in seven modes of operation: frequency (Channel
A, 5 Hz to 80 MHz), period and period averaging (Channel A,
5 Hz to 1 MHz), time interval (Channel A to Channel B, 5 Hz
to 2 MHz), counts per minute (Channel A, 5 Hz to 80 MHz),
ratio of Channel A (5 Hz to 80 MHz) divided by Channel B(5
Hz to 1 MHz), and totalize Channel A (5 Hz to 80 MHz). In
addition, Self Check mode is-provided to demonstrate
operability of most 7250A circuits.
1-3. This manual documents the 7250A Universal Counter Timer
under two categories. The standard instrument without
options and Accessories is covered in Sections 1 through 5,
7 and 8. All optional or accessory items are documented in
Section 6; refer to Table 1-1 and
1-2 for a listing of available options and Accessories chematic diagrams for the standard instrument and the
options are centralized in Section 8.
1-4. DESCRIPTION
1-5. The Model 7250A is a seven-digit universal Counter timer capable of measurements in frequency, period,
period average, time interval, totalize, ratio, and self
check mode. In addition, counts per minute mode
offers a direct readout of RPM when the instrument is
attached to an appropriate transducer. The 7250A features
six manually selected resolution settings, autoranging,
leading zero suppression, full annunciation, autoreset, and
a free-air crystal time base.
1-6. Each of the two 1 Mfl input channels is controlled by a
± slope control and a three position trigger level offset
switch. Separate attenuation controls (continuously variable
from X1 to X100) are provided for each input. A 100 kHz low
pass Filter can be applied to both channels. Channel A can
be measured in common with, or separately from, Channel B.
Input frequencies on Channel A can range from 5 Hz to 80
MHz. Channel B, when used in ratio and time interval
measurements, has a maximum input of 2 MHz.
1-7. A number of options and Accessories are available with
the instrument. Improved time base stability can be realized
with the optional TCXO, or with one of the oven time bases.
1 Manual
Service and user manual
Manual type:
Service and user manual
Pages:
150
Size:
6.1 MB
Language:
english
Revision:
Manual-ID:
P/N 487496
Date:
December 1978
Quality:
Scanned document, reading partly badly, partly not readable.
Upload date:
April 30, 2017
MD5:
6b3a2e4b-a0ec-9eab-8464-6c1ee4d67683
Downloads:
1056
Information
Instruction Manual
1 INTRODUCTION AND SPECIFICATIONS
...1-1
I-l. INTRODUCTION
...1-1
1-4. DESCRIPTION
...I-l
lr8. SPECIFICATIONS
...1-1
2 OPERATING INSTRUCTIONS
...2-1
2-1. INTRODUCTION
...2-1
2-3. SHIPPING INFORMATION
...2-1
2-5.
INSTALLATION...2-1
2-6. Input Power
...2-1
2-B. Instrument Case Mating
...2-1
2-11. Tilt-Down Baü
...2-2
2-13. Rack Installation
...2-2
2-15. OPERATING FEATURES
...2-2
2-17. OPERATION NOTES
...2-2
2-19. AC Line Connection
...2-5
2-21. Maximum Inputs
...2-5
2-23 Counter Timer Terminology
...2-5
2-64. Function Control
...2-8
2-66. Resolution
Control...2-8
2-70. Separate/Common Control
...2-8
2-72. Attenuation
Control...2-9
2-74. Slope Control
...2-9
2-76 Filter Control
...2-9
2-78. Offset Control
...2-9
2-80. Display
...2-9
2-83. Accuracy
...2-10
2-85. Dealing with One Count Error
...2-10
2-87. Reducing Time Base Error
...2-II
2-89. Trigger Error Considerations
...2-11
2-91. Reducing Errors due to Noise on the Input Signal
...2-11
2-93. Summary
...2-12
2-95. OPERATING DIRECTIONS
...2-12
2-97. Initial
Procedure...2-12
2-99. Frequency Measurements (FREQ A)
...2-12
2-101. Counts Per Minute Measurements (CPM X100A)
...2-12
2-103. Ratio Measurements (RATIO A/B)
...2-13
2-107. Period Measurements (PER A)
...2-13
2-110. Period Averging Measurements (PER AVG A)
...2-14
2-112. Time Interval Measurements (TI A-B)
...2-14
2-118. Totalizing Measurements (TOT A)
...2-15
2-120. Self-Check (CHK)
... 2-15
3 THEORY OF OPERATION
...3-1
3-1. INTRODUCTION
...3-1
3-3. FUNCTIONAL DESCRIPTION
...3-1
3-5. Frequency (FREQ A) Measurements
...3-2
3-8. Period (PER A) Measurements
...3-2
3-11. Period Averaging (PER AVG A) Measurement
...3-3
3-14. Counts Per Minute (CPM X100A)
Measurement...3-4
3-17. Ratio (RATIO A/B)
...3-5-
3-19. Totalize (TOT A)
...3-5
3-21. Time Interval (TI A-B)
...3-6
3-23. Self-Check (CHK)
...3-6
3-25. CIRCUIT ANALYSIS
...3-6
3-27 Power Supply 3-6
3-29. Time Base
...3-7
3-31. Input Circuitry
...3-7
3-34. Function Logic
...3-7
3-37. Resolution Logic
...,...3-8
3-41. Control Logic
...3-9
3-46. Main Gate Clocking Logic
...3-10
3-48. Main Gate Enable Logic
...3-10
3-51. Count Circuits
...3-11
3-54. Display
...3-12
3-56. Time Interval Logic
...3-12
3-59. Reset Logic
...3-13
3-61. Remote Logic
...3-13
4 MAINTENANCE
...4-1
4-1. INTRODUCTION
...4-1
4-3. SERVICE INFORMATION
...4-1
4-6. GENERAL
MAINTENANCE...4-1
4-7.
Disassembly...4-1
4-9. Reassembly
...4-3
4-11. Input Power
...4-3
4-13. Fuse Replacement
...4-3
4-16. Cleaning
...4-3
4-18. PERFORMANCE TEST
...4-4
4-20. Equipment Preparation
...4-4
4-22. Time Base Accuracy Test
...;...4-4
4-24. Sensitivity Test, Channel A
...4-5
4-26. Sensitivity Test, Channel B
...4-5
4-28. Display Test
...4-6
4-30. Frequency A Test
...4-6
4-32. Counts Per Minute Test
...4-7
4-34. Ratio Test
...4-8
4-36. Period Test
...4-8
4-38. Period Average
Test...4-8
4-40. Time Interval Test
...4-8
4-42. Totalize Test
...4-8
4-44. Self-Check
Test...:...4-9
4-46. CALIBRATION
...4-9
4-48. Time Base Calibration
...4-9
4-50. Coarse Time Base Adjustment
... 4-9
4-52. Channel A Trigger Level Adjustment
... 4-10
4-54. Channel B Trigger Level Adjustment
... 4-10
4-56. SELECTED COMPONENT REPLACEMENT ... 4-10
4-58. TROUBLESHOOTING
... 4-10
4-63. Static Discharge Precautions
... 4-11
5 LIST OF REPLACEABLE PARTS
... 5-1
TABLE OF CONTENTS ... 5-1
5-1. INTRODUCTION
...-... 5-2
5-4. HOW TO OBTAIN PARTS
... 5-4
6 OPTION AND ACCESSORY INFORMATION
... 6-1
TABLE OF CONTENTS ... 6-1
7 GENERAL INFORMATION
... 7-1 7A MANUAL
CHANGE INFORMATION ...
7A-1 8 SCHEMATIC DIAGRAMS
... 8-1
TABLE OF CONTENTS ... 8-1