Conrad MXD 4660 A Bedienungsanleitung Seite 11

During frequency measurement, the middle subdisplay shows the
size of the AC voltage in V. The lower subdisplay shows the deci-
bel value of the AC voltage.
For frequency measurement, switching between measurement
ranges is automatic, and manual range setting is not required/
possible.
G Logic measurements
This measurement function is for measuring logic levels in digital circuits (5 V or 12V
or 18V logic, etc.). The logic function enables you to identify the following situations:
• if the test point has a high level greater than 70 % of the Vcc (or V++ or Vc or V+,
etc.) (up to 18 VDC max., above which "OL" for overload is displayed), "Hi" is
displayed.
• if the test point has a low level smaller than 30 % of the Vcc, "Lo" is displayed.
• if there is a level of between 30 % and 70 % of the Vcc at the test point, "——" is
displayed.
This is how to measure logic level and/or set the level ranges:
1. Switch the measuring device on.
2. In the button cluster "FUNCTION", press the "LOGIC" button. The display
shows "rdY", i.e. ready for measurement.
3. Connect the black measuring lead to the COM socket, and the red measuring
lead to the V/Ohm socket.
4. Connect the free end of the black measuring lead (probe) to the ground of the
digital circuit, normally "-".
5. With the black measuring lead connected to ground, use the red measuring
probe to touch the supply point Vcc (or V++ or V+ or Vc, etc.). If this supply vol-
tage is less than 20 VDC and you repress the "SET/R" button, there is a beep
and "Hi" appears in the display.
Important!
If the supply voltage exceeds 20 VDC, there is also a beep and
"OL" (for overload) appears in the display.
6. Your multimeter is now ready to check the relevant measuring points on the
digital circuit for the corresponding logic level. Remove the red measuring pro-
be from the supply point and touch the test points you wish to test.
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Important!
During logic level measurement, the middle subdisplay shows level frequency
and the lower subdisplay shows the voltage value.
H Using the analog bar graph
The bar graph is easy to understand and operate, and is comparable to the pointer of
an analog measuring instrument, but without the mechanical disadvantages. The bar
graph is particularly appropriate for fast-changing measurement signals for which
the digital display is too slow. Trends in measurement value changes can thus be
identified and evaluated fast. The measurement rate is approx. 3-4 measurements/s.
I Using the Multimeter with a PC
a) Connection
Connect an RS-232 interface cable to both the Multimeter and a serial interface of
your PC (which should be off). Next, switch on both the measuring device and your
PC.
b) A data format is 14 bytes long and consists of the following:
BYTE 1 2 3 4 5 6 7 8 9 A B C D E
Example 1 DC - 3 .9 9 9 V
Example 2 3 .9 9 9 M o h m CR
Special features for data transmission (communication parameters):
Transfer rate :1200 baud
Character code : 7 bit ASCII
Parity : none
Stop bits : 2
Important!
The interface cable is an optional item to the software.
CR
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