23
Gossen Metrawatt GmbH
V/Hz,
, Temperature,
and A/Hz Measurements
7
Measurements
7.1 Voltage Measurement
Notes Regarding Voltage Measurement
• The multimeter may only be operated with installed batteries or
rechargeable batteries. Dangerous voltages are otherwise not
indicated, and the instrument may be damaged.
• The multimeter may only be operated by persons who are
capable of recognizing
contact hazards
and taking the appropri
-
ate safety precautions. Contact hazards exist anywhere, where
voltages of greater than 33 V RMS may occur.
The test probes may only be only gripped up to the finger
guard. Do not touch the metallic test probes under any
circumstances.
• Avoid working alone when taking measurements which involve
contact hazards
. Be certain that a second person is present.
•
Maximum permissible voltage
(METRAHIT PM XTRA / PM TUNE
/
E
XTRA
, METRAHIT PM TECH / E
TECH
)
between the connector sock
-
ets, (9 and 10) and ground (8) is 1000 V for measuring cate
-
gory III, and 600 V for measuring category IV.
•
Maximum permissible voltage
(METRAHIT EU PRO / E
SPECIAL
)
between the connector sockets (9 and 10) and ground (8) is
600 V for measuring category II.
• Be prepared for the occurrence of unexpected voltages at
devices under test (e.g. defective devices). For example, ca
-
pacitors may be dangerously charged.
• No measurements may be made with this instrument in electri
-
cal circuits with corona discharge (high-voltage).
• Special care is required when measurements are made in HF
electrical circuits. Dangerous pulsating voltages may be present.
• Be aware of the fact that dangerous voltage spikes are not displayed
during measurement with the low-pass filter.
We recommend measuring voltage without the low-pass filter first, in
order to be able to detect any dangerous voltages.
• Be absolutely certain that the measuring ranges are not
overloaded beyond their allowable capacities. Limit values are
included in chapter 10, “Technical Data”, in the table entitled
“Measuring Functions and Measuring Ranges” in the “Over
-
load Capacity” column.
Scope of Functions, Voltage Measurement
1)
A 1 kHz low-pass filter can be used in this case, in order to filter out high
frequency pulses of greater than 1 kHz, for example when performing
measurements at pulsed motor drives.
2)
Input resistance of approx. 1 M
. Erroneous displays resulting from
capacitive coupling during voltage measurement in power supply
systems are reduced to a minimum in this way.
Function
METRAHIT
PM XTRA
PM TUNE
E
XTRA
METRAHIT
PM TECH
E
TECH
METRAHIT
EU PRO
E
SPECIAL
V AC / Hz TRMS, dB
(Ri
9 M
)
1)
V AC / LP filter 1 kHz
1)
(Ri = 1 M
2)
) TRMS
V AC+DC TRMS
(Ri
9 M
)
V DC (Ri
9 M
)
MHz at 5 V AC
—
—
Duty cycle as %
—
—
Frequency bandwidth
100 kHz
20 kHz
20 kHz
