Rohde & Schwarz RT-ZC20 User manual

R&S®RT-ZC20
Current Probe
User Manual
1409781402
Version 04
(>9Ü>2)

This manual describes the following R&S products:
●R&S®RT-ZC20, Current Probe (1409.7766.02)
●R&S®RT-ZA13, Probe Power Supply (1409.7789.02)
© 2023 Rohde & Schwarz GmbH & Co. KG
Muehldorfstr. 15, 81671 Muenchen, Germany
Phone: [phone] - 0
Email: [email protected]
Internet: www.rohde-schwarz.com
Subject to change – data without tolerance limits is not binding.
R&S® is a registered trademark of Rohde & Schwarz GmbH & Co. KG.
Trade names are trademarks of the owners.
1409.7814.02 | Version 04 | R&S®RT-ZC20
The following abbreviations are used in this manual: R&S®RT-ZC20 is abbreviated as R&S RT-ZC20, and
R&S®RT-ZA13 is abbreviated as R&S RT-ZA13.

Contents
R&S®RT-ZC20
3User Manual 1409.7814.02 ─ 04
Contents
1 Safety and regulatory information....................................... 5
1.1 Safety instructions................................................................................5
1.2 Labels on the product.......................................................................... 7
1.3 Warning messages in the documentation.......................................... 8
2 Product description...............................................................9
2.1 Key features.......................................................................................... 9
2.2 Unpacking and checking......................................................................9
2.3 Description of the probe.................................................................... 10
3 Connecting the probe..........................................................13
3.1 Handling the probe............................................................................. 13
3.2 Connecting the probe to the power supply......................................14
3.3 Connecting the probe to the oscilloscope....................................... 15
3.4 Setting up and demagnetizing...........................................................16
3.5 Connecting the probe to the DUT......................................................17
3.6 Considerations for measurements....................................................19
4 Maintenance and service.................................................... 22
4.1 Cleaning...............................................................................................22
4.2 Contacting customer support............................................................22
4.3 Returning for servicing...................................................................... 23
4.4 Calibration interval............................................................................. 23
4.5 Storage and transport........................................................................ 24
4.6 Disposal............................................................................................... 24
5 R&S RT-ZA13 probe power supply.................................... 25

Contents
R&S®RT-ZC20
4User Manual 1409.7814.02 ─ 04

Safety and regulatory information
R&S®RT-ZC20
5User Manual 1409.7814.02 ─ 04
1 Safety and regulatory information
The product documentation helps you to use the product safely and efficiently.
Follow the instructions provided here and in the Chapter 1.1, "Safety instructions",
on page 5.
Intended use
The product is intended for the development, production and verification of elec-
tronic components and devices in industrial, administrative, and laboratory envi-
ronments. Use the product only for its designated purpose. Observe the operating
conditions and performance limits stated in the data sheet.
Where do I find safety information?
Safety information is part of the product documentation. It warns you of potential
dangers and gives instructions on how to prevent personal injury or damage
caused by dangerous situations. Safety information is provided as follows:
●In Chapter 1.1, "Safety instructions", on page 5. The same information is
provided in many languages as printed "Safety Instructions". The printed
"Safety Instructions" are delivered with the product.
●Throughout the documentation, safety instructions are provided when you
need to take care during setup or operation.
1.1 Safety instructions
Products from the Rohde & Schwarz group of companies are manufactured
according to the highest technical standards. To use the products safely, follow
the instructions provided here and in the product documentation. Keep the prod-
uct documentation nearby and offer it to other users.
Use the product only for its intended use and within its performance limits. Inten-
ded use and limits are described in the product documentation such as the data
sheet, manuals and the printed "Safety Instructions". If you are unsure about the
appropriate use, contact Rohde & Schwarz customer service.
Using the product requires specialists or specially trained personnel. These users
also need sound knowledge of at least one of the languages in which the user
interfaces and the product documentation are available.
Safety instructions

Safety and regulatory information
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6User Manual 1409.7814.02 ─ 04
Reconfigure or adjust the product only as described in the product documentation
or the data sheet. Any other modifications can affect safety and are not permitted.
Never open the casing of the product. Only service personnel authorized by
Rohde & Schwarz are allowed to repair the product. If any part of the product is
damaged or broken, stop using the product. Contact Rohde & Schwarz customer
service at https://www.rohde-schwarz.com/support.
In these safety instructions, the term "product" covers instruments (oscillo-
scopes), probes and their accessories.
Choosing the operating site
Only use the product indoors. The product casing is not waterproof. Water that
enters can electrically connect the casing with live parts, which can lead to elec-
tric shock, serious personal injury or death if you touch the casing. If
Rohde & Schwarz provides accessories designed for outdoor use of your product,
e.g. a protective cover, you can use the product outdoors.
Unless otherwise specified in the data sheet, you can operate the product up to
an altitude of 2000 m above sea level.
The product is suitable for pollution degree 2 environments where nonconductive
contamination can occur. For more information on environmental conditions such
as ambient temperature and humidity, see the data sheet.
Performing measurements
Take the following measures for your safety:
●Observe all voltage and current ratings of the instrument, the probes, and the
accessories. Exceeding the allowed limits can lead to an electric shock.
Limits and ratings are marked on the products and listed in the data sheets.
Consider that the rated values depend on the frequency. The limitation curves
or values are provided in the data sheet.
●Never cause any short circuits when measuring sources with high output cur-
rents.
●When working with current probes, observe the additional operating condi-
tions specified in these safety instructions.
●Prevent the probe from receiving mechanical shock. Avoid putting excessive
strain on the probe cable or exposing it to sharp bends. Touching a broken
cable during measurements can cause injuries.
●Set up all probe connections to the instrument before applying power.
Safety instructions

Safety and regulatory information
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7User Manual 1409.7814.02 ─ 04
Working with current probes
When working with current probes, you can measure high-frequency currents or
currents that contain high-frequency components.
●Switch off the test circuit while connecting the probe.
●Do not attach the clamp to bare unisolated conductors. To avoid injury from a
short circuit, measure at a location on an insulated wire where the insulation is
sufficient for the circuit voltage.
●Connect the probe only to the secondary side of a breaker. With this measure,
you avoid injury, if a short circuit occurs.
●The following effects can cause burns and fire or damage to the measurement
site:
– Eddy current loss can cause heating of the sensor head.
– Dielectric heating can cause heating of cord insulation and other materials.
●When measuring current that includes a high-frequency component, consider
the derating characteristics of the probe. Do not measure any current that
exceeds the rated current.
●Using the probes with high frequencies or strong magnetic fields may cause
the device to become abnormally hot, resulting in fire, equipment damage, or
burns.
1.2 Labels on the product
Labels on the casing inform about:
●Personal safety
●Product and environment safety
●Identification of the product
Table 1-1: Meaning of safety labels
Potential hazard
Read the product documentation to avoid personal injury or product damage.
Hazardous contact voltages
Do not use the probe at uninsulated live lines. Make sure to measure at sufficiently
insulated conductors. This measure protects you against electric shock, electric burn,
or arc flash.
Labels on the product

Safety and regulatory information
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Table 1-2: Labels regarding product and environment safety
Labeling in line with EN 50419 for disposal of electrical and electronic equipment after
the product has come to the end of its service life.
1.3 Warning messages in the documentation
A warning message points out a risk or danger that you need to be aware of. The
signal word indicates the severity of the safety hazard and how likely it will occur
if you do not follow the safety precautions.
WARNING
Potentially hazardous situation. Could result in death or serious injury if not avoi-
ded.
CAUTION
Potentially hazardous situation. Could result in minor or moderate injury if not
avoided.
NOTICE
Potential risks of damage. Could result in damage to the supported product or to
other property.
Warning messages in the documentation

Product description
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9User Manual 1409.7814.02 ─ 04
2 Product description
The R&S RT-ZC20 is an AC/DC current probe. It allows the user to make current
measurements from DC to 100 MHz. By clamping on the conductor to be mea-
sured, the current waveform is captured easily without interrupting the electric cir-
cuit.
2.1 Key features
The R&S RT-ZC20 is an AC/DC current probe. It allows the user to make current
measurements from DC to 100 MHz. By clamping on the conductor to be mea-
sured, the current waveform is captured easily without interrupting the electric cir-
cuit.
The key features of the probe are the following:
●Highly accurate current detection.
●Easy current measurement without interrupting the electric circuit.
●Broadband frequency characteristics DC to 100 MHz.
●Permits measurement of low current levels.
●Easy protection function to avoid self-heating during excessive input.
●Unique thin film Hall effect element.
2.2 Unpacking and checking
1. Unpack the product carefully.
2. Retain the original packing material. Use it when transporting or shipping the
product later.
3. Using the delivery notes, check the equipment for completeness.
4. Check the equipment for damage.
If the delivery is incomplete or equipment is damaged, contact
Rohde & Schwarz.
Unpacking and checking

Product description
R&S®RT-ZC20
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Delivery notes
The delivery contains the following items:
●User manual
●Carrying case
●R&S RT-Zxx high-voltage and current probes data sheet
●Safety instructions for oscilloscopes and accessories (multilingual)
●Calibration certificate
●Documentation of calibrated values
2.3 Description of the probe
1 = Sensor
2 = Terminator
3 = Sensor cable
4 = Power supply cable
5 = Current direction indication
6 = UNLOCK indication
Description of the probe

Product description
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11User Manual 1409.7814.02 ─ 04
7 = Opening lever
8 = Sensor head
9 = Demagnetizing switch (DEMAG)
10 = Zero adjustment dial (ZERO ADJ)
11 = Coarse adjustment trimmer
12 = Output connector
13 = Power plug
Sensor head
The sensor head clamps on the conductor being measured, and carries out the
actual current measurement. It is a precision assembly including a molded com-
ponent, a ferrite core, and a Hall effect element. It may be damaged if subjected
to sudden changes in ambient temperature, or mechanical strain or shock, and
therefore great care should be exercised in handling it.
See also "Handling the sensor head" on page 13.
Opening lever
Operating lever for opening the sensor head. Always use this lever to open the
sensor head.
Demagnetizing switch (DEMAG)
This demagnetizes the core if it has been magnetized by switching the power on
and off, or by an excessive input. Always carry out demagnetizing before mea-
surement.
Zero adjustment dial (ZERO ADJ)
Use the zero adjustment dial to correct for the effect of a voltage offset or temper-
ature drift.
When beginning measurement, after demagnetizing always carry out a zero
adjustment.
Coarse adjustment trimmer
Use this only when adjustment is not possible within the range of the zero adjust-
ment. Use a nonconductive screwdriver (e.g. ceramic driver) for adjustment.
Output connector
Connect to the BNC input connector of the waveform measuring instrument.
The current waveform of the measured conductor is output at a constant rate
(0.1 V/A).
Description of the probe

Product description
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12User Manual 1409.7814.02 ─ 04
Power plug
Connect the plug to the R&S RT-ZA13 probe power supply receptacle to supply
power to the sensor.
Description of the probe

Connecting the probe
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3 Connecting the probe
3.1 Handling the probe
The R&S RT-ZC20 can withstand a moderate amount of physical and electrical
stress. To avoid damage, treat the probe with care:
●Prevent the probe from receiving mechanical shock.
●This device should be installed and operated indoors only, between 0°C and
40°C (32°F to 104°F) and 80% RH or less.
●Avoid strain on the probe cable and route it carefully. Keep the cable away
from heat sources, as bare conductors could be exposed if the insulation
melts.
●Do not spill liquids on the probe.
Handling the sensor head
The sensor head is a precision assembly including a molded component, a ferrite
core, and a Hall effect element. To avoid damage, treat it with care:
●Do not subject it to sudden changes in ambient temperature.
●If the mating surfaces are scratched, performance may be impaired. Prevent
the mating surfaces of the sensor head from being scratched:
– Keep the sensor head closed when not in use, to avoid accumulating dust
or dirt.
– Measurements are degraded by dirt on the mating surfaces of the sensor
head, so keep the surfaces clean by gently wiping with a soft cloth.
– Keep the clamp jaws and core slits free from foreign objects, which could
interfere with clamping action.
– When the power is on, keep the core section of the sensor closed, except
when clamping it onto the conductor to be measured. The mating surface
of the core section can be scratched while it is open.
Electromagnetic compatibility
The electromagnetic compatibility (EMC) class indicates where you can operate
the product. The product is rated in EMC class B, see also data sheet under
"General data".
Handling the probe

Connecting the probe
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Class B equipment is suitable for use in:
●Residential environments
●Environments that are directly connected to a low-voltage supply network that
supplies residential buildings
3.2 Connecting the probe to the power supply
1. Have the R&S RT-ZA13 probe power supply, and an oscilloscope or waveform
measuring instrument ready.
2. NOTICE! Voltage check. When using a different power supply than the
R&S RT-ZA13 probe power supply, before turning on the power, make sure
that the voltage of the used power supply matches the supply voltage indica-
ted in the data sheet "R&S RT-Zxx high voltage and current probes".
Turn off the power switch at the rear of the R&S RT-ZA13 probe power supply.
3. Connect the power cord.
4. Connect the power plug of the R&S RT-ZC20 to the power receptacle of the
R&S RT-ZA13 probe power supply.
5. Check that the conductor being measured is not clamped when supplying
power to the R&S RT-ZC20. When power is turned on, a demagnetizing wave-
form is initially applied to the output. This is intentional in the design, and not a
fault.
6. Turn on the power switch of R&S RT-ZA13 probe power supply. Ensure that
the front panel power indicator lights.
Connecting the probe to the power supply

Connecting the probe
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7. Connect the R&S RT-ZC20 to the oscilloscope, as described in Chapter 3.3,
"Connecting the probe to the oscilloscope", on page 15.
3.3 Connecting the probe to the oscilloscope
●The output of this device is terminated internally. Use a high impedance
input of the measuring instrument. With an input impedance of 50 Ω,
accurate measurement is not possible.
●If using BNC-banana plug adapters or similar to connect to input termi-
nals other than BNC connectors, make sure the polarity is correct.
To connect the probe:
1. Insert the output connector of the R&S RT-ZC20 into one of the BNC input
connectors of the oscilloscope.
2. Turn the collar until it clicks.
3. Ensure that the collar is locked securely.
Figure 3-1: Connecting the probe to the Rohde & Schwarz oscilloscope
4. Configure the probe connection at the oscilloscope.
The exact procedure depends on the used instrument and is described in the
oscilloscope's user manual. Supported oscilloscopes are listed in the R&S RT-
Zxx data sheet.
Make sure to set the following:
● Vertical unit = Ampere
● Coupling = DC
● Termination = 1 MΩ
Connecting the probe to the oscilloscope

Connecting the probe
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16User Manual 1409.7814.02 ─ 04
● Manual Gain = 0.1 V/A
Alternatively, select "Predefined probe" = R&S RT-ZC20 if this selection is
available on the instrument.
To disconnect the probe:
1. Turn the collar until it is unlocked.
2. Pull the connector away from the oscilloscope.
3.4 Setting up and demagnetizing
1. With the waveform measuring instrument input at ground, adjust the waveform
to the zero position.
2. Connect the R&S RT-ZC20 current probe to the power supply as described in
Chapter 3.2, "Connecting the probe to the power supply", on page 14.
3. Connect the R&S RT-ZC20 current probe to the oscilloscope as described in
Chapter 3.3, "Connecting the probe to the oscilloscope", on page 15.
4. NOTICE! Risk of circuit damage. Demagnetizing causes current to flow into
the conductor, which may damage parts in the circuit to be measured. Do not
demagnetize while the R&S RT-ZC20 is clamping a conductor to be mea-
sured.
Make sure that there is no conductor in the sensor aperture.
5. Press the opening lever until the UNLOCK indication disappears. Ensure that
the sensor head is properly closed.
6. Press the demagnetizing switch (DEMAG) on the terminator.
Setting up and demagnetizing

Connecting the probe
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17User Manual 1409.7814.02 ─ 04
The demagnetizing process takes about one second. During demagnetizing, a
demagnetizing waveform is shown on the oscilloscope. The positive and neg-
ative components of this waveform may be asymmetrical.
7. Turn the zero adjustment dial on the terminator to adjust the trace to the zero
position.
8. If zero adjustment is not possible, turn the coarse adjustment trimmer to bring
the trace within the range of adjustment by the zero adjustment dial, see
Chapter 2.3, "Description of the probe", on page 10.
Note: Use the trimmer carefully to prevent damaging it. Use a flathead screw-
driver that is made of non-conductive material like ceramics. Recommended
tip shape: thickness 4 mm, width 1.8 mm, length 10 mm or longer.
3.5 Connecting the probe to the DUT
1. Check that the system is safe, and that the preparations described in the pre-
ceding sections have been carried out.
2. Pull the sensor slider, so that the clamp opens.
3. Align the sensor so that the current direction indication matches the direction
of current flow through the conductor that you measure. The conductor should
be in the center of the clamp aperture because the measurement may be
affected by the position within the clamp aperture of the conductor being mea-
sured.
4. Press the opening lever until the UNLOCK indication disappears. Make sure
that the sensor head is properly closed.
Connecting the probe to the DUT

Connecting the probe
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If the sensor head is not properly closed, accurate measurement is not possi-
ble.
The current consumption of clamp-on probes depends on the current to be mea-
sured. Confirm that the total current consumption of the probes does not exceed
the rated output current of the R&S RT-ZA13 probe power supply.
Figure 3-2: Current consumption* vs. current to be measured (typical)
*The sum total of positive and negative current consumption.
Connecting the probe to the DUT

Connecting the probe
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19User Manual 1409.7814.02 ─ 04
3.6 Considerations for measurements
Measurements of continuous input current
To avoid damage to the probe when doing measurements of continuous input cur-
rent, consider the following:
●The maximum continuous input range is based on heat that is internally gen-
erated during measurement. It varies according to the frequency of the current
being measured. Refer to the data sheet "R&S RT-Zxx high voltage and cur-
rent probes".
●The device may sustain damage from self-heating even at current levels that
are lower than the maximum rated current. The maximum rated current is a
recommended value that assumes sine-wave input under standard conditions.
Self-heating may happen if the ambient temperature increases or the mea-
surement current waveform contains other frequency components.
●If the input current exceeds a certain level, generated heat activates a built-in
safety function that blocks normal output. If this happens, remove the input
immediately (remove the sensor from the conductor being measured, or
reduce the input current to zero). Wait until the sensor has had sufficient time
to cool before resuming operation.
Continuous input of current exceeding the rated maximum or repeated activa-
tion of the safety function may result in damage to the device.
●Even if the input current does not exceed the rated continuous maximum cur-
rent, continuous input for an extended period of time may result in activation
of the safety circuit to prevent damage resulting from heating of the sensor.
At high ambient temperatures, the built-in safety circuit may activate at current
input levels below the rated continuous maximum current.
●Current measurement exceeding approx. 1 kHz may result in temperature rise
on the sensor-head. This is attributed to excitation loss that cannot be preven-
ted due to natural physical principles. Be careful to avoid injury, electric shock
due to short-circuits, or damage to the device that may be caused by the
increased temperature.
●Do not place any unclamped conductor with an electric current of a frequency
of 10 kHz or more near the sensor head. Current flowing in the conductor
nearby may heat up the sensor head and cause its temperature to rise, lead-
ing to damage to the sensor. For example, when one side of a go-and-return
conductor is clamped and the other side is also placed near the sensor head
as shown in the diagram, even if the electric current is lower than the consec-
Considerations for measurements

Connecting the probe
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20User Manual 1409.7814.02 ─ 04
utive maximum current, electric currents in both sides will heat up the sensor
and raise the temperature, thereby causing damage to the sensor.
Drift, oscillation, and sound
●Immediately after powering on, the probe may be subject to an appreciable
offset drift due to the effect of self-heating. Therefore, warm up the probe for
about 30 minutes before carrying out measurements.
●When performing continuous measurements, be aware that the offset voltage
drifts, depending on factors such as the ambient temperature.
●Under certain circumstances, oscillation may occur while the power supply is
on. This does not indicate a malfunction. Oscillation can be stopped and oper-
ation restored to normal by opening and closing the sensor head.
●Acoustic resonance can occur depending on the amplitude and frequency of
the measured current. This sound may also occur during demagnetizing oper-
ation, but it is not a malfunction or probe failure.
If a foreign substance such as dust is present on the contact surfaces of the
sensor head, a slight gap can occur between the upper and lower sensors,
and a resonant sound may be emitted. Clean the sensors as described in this
manual to ensure correct measurements.
●An increasing volume of the resonant sound during use may indicate that the
gap between the upper and lower sensors has increased. Since the sensor
characteristics may change, it is recommended to calibrate the device.
Considerations for measurements