The Autocal Procedure - Fluke PM3082 Service Manual

CORRECTIVE MAINTENANCE PROCEDURES
For D1112 (unit A3) refer to the table below:
Y-value
X.6
X.4
X.2
X.8
X.1
X.3
X.5
X.7
X.12
X.11
X.10
X.15
X.9
X.O
X.14
X.13
IMPORTANT:
8.13

THE AUTOCAL PROCEDURE

8.13.1 Introduction
The oscilloscopes PM3094/92/84/82 have an autocal function. After pushing the CAL key for more
than 2 seconds, a big number of adjustments are performed automatically. The advantages are:
- high measuring accuracy
- considerable gain of time. The manual calibration adjustment is limited to a job of half an hour.
The autocal procedure consists of a number of adjustment steps that are performed in sequence.
Each step comprises a series of attempts - via 'successive approximation' - to obtain the ideal
adjustment. The procedure is controlled by the instrument's microprocessor. The internal references
are a very accurate 10 volt source and a quartz crystal.
During a calibration step, a defined stimulus is applied at a certain point in the circuit (the input).
The response is measured at a later point in the circuit (the output). Somewhere inbetween, a
digital-to-analog-converter (DAC) influences the performance of the circuitry. The DAC output is
varied such that the output response has the desired value.
Pin number
16
19
21
13
22
20
18
17
9
10
11
6
12
23
7
8
After having completed these tests, it is recommended to reset the oscilloscope.
Therefore press the keys 'STATUS' a n d 'TEXT OFF' simultaneously.
Pin name
POS CH1
POS CH2
POS CH3
POS CH4
VAR CH1
VAR CH2
VAR CH3
VAR CH4
VAR MTB
LEVEL MTB
LEVEL DTB
INTENS TEXT
TRACE SEP
FOCUS-DA
HOLD OFF
INTENS TRACE
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