Tektronix DM 5010, Инструкция по эксплуатации

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Operating Instructions —DM 5010
5
CAUTION <
To avoid equipment damage, do not apply a voltage
exceeding 42.4 V peak ac or 60 V de between pins
28B (Hi) and 28A (Lo) of the rear-interface connector
P1031 on the ADC board (A 17).
> CAUTION <
cathode to the LOW. Devices that can be checked are those
having a voltage drop under 1.999 volts. These include most
diodes and some LEDs.
To check the reverse voltage drop, reverse the diode
connections to the instrument. The display window should
display OC.
Do not switch from front-pane! to rear interface input
while over 500 V peak is appiied to the front panei
input connectors. Instrument damage and erratic op­
eration may result.
DC Voltage Measurements
When the DCV button is pressed, the DM 5010 mea­
sures dc voltages using the following ranges: 200 mV, 2 V,
20 V, 200 V, and 1000 V. The readout displays a positive
sign when the input to the HIGH connector is positive with
respect to the LOW connector. Observe the maximum input
voltage ratings.
Resistance Measurements
Pressing the OHMS button enables the DM5010 to
measure resistance using these ranges: 200 Ω, 2 kΩ, 20 kΩ,
200 kΩ, 2 MΩ, and 20 MΩ. Conventional current flow is from
the HIGH connector to the LOW connector. Refer to Table
2-3 for the value of current and maximum voltages across
the
input connectors for full scale display readings (instru­
ment not over-ranged). The maximum (open circuit) voltage
available from the HIGH connector referenced to the LOW
connector is less than 5 V.
Ac Voltage Measurements
The DM 5010 provides two ac measurement functions.
True rms ac voltages are measured and displayed using the
ACV function. True rms ac voltages elevated to a dc level
are measured and displayed using the ACV+DCV function.
Ranges for both functions are 200 mV, 2 V, 20 V, 200 V,
and 700 V. Voltages can be measured with a crest factor up
to four at full scale. The crest factor is the ratio of the peak
voltage to rms voltage. Observe the maximum input voltage
ratings. The LOW FREQ RESPONSE function provides a
stable display for low-frequency ac measurements. When
activated, this function displays the average of four ac
measurements.
Conversion Rates
The DM 5010 operates at either of two conversion rates.
The FAST rate (CONVERSION RATE button illuminated)
makes measurements at the maximum rate specified for the
selected function. Measurements are displayed using 3 1/2
digits. With the button not illuminated, the instrument makes
measurements at the normal rate specified for the selected
function and uses a 4 1/2 digit display.
Table 2-3
SOURCE VOLTAGES
(OHMS FUNCTION)
Range Typical Current
(0 Ω to Full Scale)
V Max
(Full Scale)
200 Ω 1.02 mA to 1 mA
2 kΩ 0.12 mA to 0.1 mA
20 kΩ 9.2 µA to 10 µA 0.2 V
200 kΩ 1.08 µA to 1 µA
2 MΩ 0.12 µA to 0.1 µA
20 MΩ 0.12 µA to 0.04 µA 0.8 V
Measuring Diodes
Pressing the DIODE TEST button causes the DM 5010
to generate a 1 mA dc current at the HIGH connector. The
forward voltage drop of diode junctions is measured by con­
necting the diode anode to the HIGH connector and the
Triggering
The DM 5010 has two front-panel trigger modes, RUN
and TRIGGERED. When the RUN button is pressed, con­
versions are free-running at the selected conversion rate.
Pressing the TRIGGERED button causes the instrument to
trigger one measurement each time the button is pressed.
In addition, conversions may be triggered via the rear
interface connector, pin 16A and 16B (Lo) on the Isolation
board (A15). Use of this feature requires installation of an
internal jumper. Refer qualified service personnel to the
Maintenance section of this manual for additional informa-
tion. Installation of this jumper enables the EXTRIG trigger
function in addition to the RUN and TRIGGERED functions.
To use the EXTRIG trigger, activate the TRIGGER button to
disable
the instrument’s free-running trigger. The EXTRIG
requires a negative-going TTL compatible signal to initiate
the
internal trigger. To cause a single trigger, this line must
be held low between 0.5 and 10 µsec. If held low for a longer
time, the instrument triggers multiple measurements.
REV JAN 1982
2-9