Simpson 260-8XPI, Инструкция по эксплуатации, Страница: 13 / 28

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energized. A mistake could damage the instrument and cause personal in-
jury.
j. Locate all voltage sources and accessible current paths before making con-
nections to circuitry.
k. Make certain that the equipment being worked upon is properly grounded
and fuses are of the proper type and rating.
l. Double check switch positions and jack connections before applying power to
the Instrument.
m. Remain alert for low voltage circuits which may be floating at high voltage
with respect to earth ground and for composite voltages (AC + DC) such as
are found in r-f amplifiers. The floating voltage or composite voltage must not
exceed the Instrument’s rated maximum circuit-to-ground voltage.
n. Do not make electrical measurements where the air may contain explosive
concentrations of gas or dust such as in mines, grain elevators, gasoline sta-
tions or in the presence of charging batteries until determined to be safe by
qualified personnel. Note that even metallic dusts can be explosive.
o. No General Purpose VOM is to be used to make electrical measurements on
blasting circuits or blasting caps.
3.2 Operational Items and Features
Table 3-1 describes the function of all the items used to operate the Instrument.
These items are illustrated in Figure 3-1. Become familiar with these items prior
to operating the Instrument for the first time.
Table 3-1. Operating Items and Features
1. Range Switch: Twelve positions: May be rotated 360° in either
direction to select any of the five AC & DC volt-
ages, four DC currents & three resistance ranges.
2. Function Switch: The function switch has four positions: (Audio),
+DC, -DC, and AC Volts only. To measure DC cur-
rent or voltage, set function switch to the -DC or
+DC position, depending on polarity of the signal
applied across the test leads. To measure AC volt-
age set the function switch to the AC position. For
resistance measurement, switch may be set in ei-
ther the +DC or -DC position. Polarity of the inter-
nal ohm meter battery voltage will be as marked
at the jacks when switch is in the +DC position
and reversed in the -DC position.
3. Zero Ohms: This control is used to compensate for variation in
the voltage of the internal batteries when making
resistance measurements.