12227 Simpson, 12227 Datasheet - Page 16

• Manufacturer Part Number: 12227
• Description: Analog Multimeters 270-5RT VOM HI A
• Manufacturer: Simpson

Specifications of 12227

• Accuracy: +/- 1.75 %
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

4.7
4.8
a.
b.
c.
When in doubt as to the voltage present,
always use the highest voltage range
as a protection to the Instrument. If the
voltage is within a lower range, the
switch may be set for the lower range to
obtain a more accurate reading.
IMPORTANT: Be sure power is off in the
circuit being measured and all capaci-
tors discharged.
d.
e.
f.
Turn off power to the circuit and wait until the meter indicates zero before discon-
necting the test leads.
Use extreme care when working with high voltage circuits. Do not touch the
Instrument or test leads while power is on in the circuit being measured.
Before proceeding with the following steps, review Safety Precautions in Para-
graph 4.1.
a.
b.
c.
d.
0-10. Then divide the reading by 10.
DC Voltage Measurement 0-2.5 Through 0-500V Range.
Set the function switch at + DC (Figure 4-1).
Plug the black test lead into the -
COMMON jack and the red test lead
into the + jack.
Set the range switch at one of the
five voltage range positions marked
2.5V, 10V, 50V, 250V or 500V.
Connect the black test lead to the
negative side of the circuit being
measured and the red test lead to
the positive side of the circuit.
Turn on the power in the circuit be-
ing measured.
Read the voltage on the black scale marked DC. For the 2.5V range, use the
0-250 figures and divide by 100. For the 10V, 50V, and 250V ranges, read the
figures directly. For the 500V range, use the 0-50 figures and multiply by 10.
DC Voltage Measurement 0-1000V Range
Set the function switch at + DC (Figure 4-1).
Set the range switch at 1000V (dual position with 500V).
Plug the black test lead into the - COMMON jack and the red test lead into the
1000V jack.
Be sure power is off in the circuit being measured and all capacitors dis-
16
!
Figure 4-1. Jacks and Switch
Positions for Measuring DC Voltages
COMMON
+D.C.
READ MANUAL BEFORE USE
-D.C.
WARNING
+1V.
10V.
2.5V.
1V
50V
µAMPS
250V.
500V
1000V
ALL TERMINALS 1KV. MAX.
270
+50 µAMPS.
250MV.
AC.
1000V
D.C
4.9
Range
e.
f.
g.
Turn off power to the circuit and wait until the meter indicates zero before discon-
necting the test leads.
Branch and distribution circuits (120/240/480V etc.) can deliver dangerous ex-
plosive power momentarily into a short circuit before the fuse/breaker opens the
circuit. Make sure that the Instrument switches are set correctly, jacks are prop-
erly connected, and that the circuit power is turned off before making connections
to such circuits.
The 270 responds to the average value
of an AC waveform. The Dial is cali-
brated in terms of the RMS value of a
pure sine wave. If the waveform is non-
sinusoidal, and depending upon its
waveform, the reading may be either
higher or lower than the true RMS value
of the measured voltage. Thus an error
may be introduced if the 270 is used to
measure a non-sinusoidal waveform.
Also, accuracy is lessened at higher in-
put frequencies (Figure 4-2).
Before proceeding with the following
steps, review the Safety Precautions in
Paragraph 4.1.
a.
b.
c.
d.
charged.
Connect the black test lead to the negative side of the circuit being measured
and the red test lead to the positive side of the circuit.
Turn on power in circuit being measured.
Read the voltage using the 0-10 figures on the black scale marked DC.
Multiply the reading by 100.
AC Voltage Measurement 0-2.5 Through 0-500V
Set the function switch at AC (Fig-
ure 4-3).
Set the range switch at one of the
five voltage range positions marked
2.5V, 10V, 50V, 250V or 500V.
When in doubt as to actual voltage present, always use the highest voltage
range as a protection to the Instrument. If the voltage is within a lower range,
the switch may be set for the lower range to obtain a more accurate reading.
Plug the black test lead into the - COMMON jack and the red test lead into the
+ jack.
Turn off power to the circuit to be measured and discharge any capacitors.
17
!
!
Figure 4-2. Frequency Response,
AC Voltage Ranges
COMMON
+D.C.
READ MANUAL BEFORE USE
-D.C.
WARNING
+1V.
2.5V.
1V
10V.
50V
µAMPS
250V.
500V
1000V
ALL TERMINALS 1KV. MAX.
270
+50 µAMPS.
250MV.
AC.
1000V
D.C