®
R&S
RT-ZVC
Multi-Channel Power
Probe
User Manual
(=JEW2)
1326213902
Version 03
User Manual
This user manual describes the following R&S®RT-ZVC models:
●
R&S®RT-ZVC04 2x4 voltage/current channels for R&S®RTO2000/RTE
(1326.0259.04 )
●
R&S®RT-ZVC02 2x2 voltage/current channels for R&S®RTO2000/RTE
(1326.0259.02 )
●
R&S®RT-ZVC04 2x4 voltage/current channels for R&S®CMWrun
(1326.0259.24 )
●
R&S®RT-ZVC02 2x2 voltage/current channels for R&S®CMWrun
(1326.0259.22 )
●
R&S®RT-ZVC04A 2x4 voltage/current channels with autoranging for
R&S®CMWrun (1326.0259.34 )
●
R&S®RT-ZVC02A 2x2 voltage/current channels with autoranging for
R&S®CMWrun (1326.0259.32 )
© 2018 Rohde & Schwarz GmbH & Co. KG
Mühldorfstr. 15, 81671 München, Germany
Phone: +49 89 41 29 - 0
Fax: +49 89 41 29 12 164
Email: info@rohde-schwarz.com
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.
1326.2139.02 | Version 03 | R&S®RT-ZVC
The following abbreviations are used in this manual: R&S®RT-ZVC is abbreviated as R&S RT-ZVC.
R&S®CMWrun is abbreviated as R&S CMWrun. R&S®RTO2000 and R&S®RTE are abbreviated as
R&S RTx. R&S®RTO-B1E and R&S®RTE-B1E are abbreviated as R&S RTx-B1E.
R&S®RT-ZVC
Contents
Contents
1 Product Description.............................................................. 5
1.1 Prerequisites......................................................................................... 6
1.2 Key Characteristics.............................................................................. 6
1.3 Unpacking the Instrument....................................................................8
1.4 Instrument Overview............................................................................ 9
1.4.1 Probe Box............................................................................................. 10
1.4.2 Cables and Accessories....................................................................... 13
1.5 Optional Accessories......................................................................... 14
2 Putting into Operation.........................................................17
2.1 Test Setup with Oscilloscope............................................................ 19
2.2 Test Setup with R&S CMWrun........................................................... 20
2.3 Connecting the Probe to the DUT..................................................... 22
3 Measurement Principles..................................................... 24
3.1 Solder-In Connection..........................................................................24
3.2 Signal Integrity.................................................................................... 26
3.2.1 Ground Connection...............................................................................27
3.2.2 Electromagnetic Interference................................................................ 27
3.2.3 Accuracy............................................................................................... 28
3.2.4 Dynamic Range and Operating Window...............................................28
3.3 Probing Philosophy............................................................................ 29
3.3.1 Signal Flow for Oscilloscope Operation................................................ 29
3.3.2 Signal Flow for R&S CMWrun Operation (USB IF Only).......................30
3.3.3 Internal Shunt Operation.......................................................................31
3.3.4 External Shunt Operation......................................................................32
3.3.5 Autoranging Mode.................................................................................33
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R&S®RT-ZVC
Contents
4 Maintenance and Service....................................................35
4.1 Service Strategy..................................................................................35
4.2 Returning the Probe for Servicing.................................................... 35
4.3 Cleaning...............................................................................................35
4.4 Calibration Interval............................................................................. 36
4.5 Discarding the Probe..........................................................................36
Index..................................................................................... 37
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R&S®RT-ZVC
Product Description
1 Product Description
The R&S RT-ZVC is a multi-channel power probe with integrated 2- or 4-channel
amperemeter and 2- or 4-channel voltmeter. It provides parallel measurements of
analog or digital, voltage/current signals with excellent 18-bit resolution. Integrated post-processing logic calculates power and statistical results with high accuracy.
The R&S RT-ZVC is a useful measurement instrument for such applications as
for example:
●
Embedded electronics
●
Battery-driven devices (wearables, smartphones)
●
Power supply of integrated circuits
●
Battery life-time measurements
●
Power consumption measurements
●
Energy-harvesting
The multi-channel power probe is developed for tests with R&S CMWrun and for
operation with an oscilloscope.
Table 1-1: Variants of setup with R&S RT-ZVC
Operation with an oscilloscope Standalone device with R&S CMWrun
Embedded electronics/circuit measurements,
sophisticated processing
●
Data transferred via digital interface at full
sample rate of 5 MSa/s
●
Probe powered by scope
System-level power measurements using
R&S CMWrun, reduced sample rate via USB
●
Data transferred via USB to the
R&S CMWrun controller PC
●
Externally powered
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R&S®RT-ZVC
Product Description
Key Characteristics
1.1 Prerequisites
●
Operation with oscilloscope
– Oscilloscope of type R&S RTO2000 equipped with R&S RTO-B1E or
– R&S RTE equipped with R&S RTE-B1E is required.
Note, that old R&S RTx-B1 boards cannot run R&S RT-ZVC.
●
Operation with R&S CMWrun
– R&S CMWrun, version 1.8.8 and later. The option R&S CMW-KT051 of
R&S CMWrun for general-purpose tests is required.
– Windows supported operating system includes Windows 7 and Windows
10 (32-bit or 64-bit version).
– A Rohde & Schwarz-specific driver is required to be installed at the run
PC, to support USB3.0 SuperSpeed (SS) interface.
With the installed driver, no additional connection configuration is required.
The probe acts as a plug-and-play device.
The driver is delivered with the R&S CMWrun SW.
1.2 Key Characteristics
The R&S RT-ZVC probe houses integrated voltmeter, amperemeter, and postprocessing logic. The probe performs built-in A/D conversion and signal post-processing. Within integrated post-processing, the R&S RT-ZVC calculates power
and statistical results (min/max/avg/RMS). It measures the differential and common mode AC and DC signals simultaneously.
The following figure illustrates the scheme of a probe with four voltage and four
current channels.
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R&S®RT-ZVC
Product Description
Key Characteristics
+
-
+
-
+
-
4x Amperemeter
+
-
+
-
+
-
+
4x Voltmeter
-
+
-
A
A
A
A
A
A
A
A
Figure 1-1: Electrical scheme
D
Power Supply
DC/DC
D
D
USB
D
D
Post-
processing
Logic
HDMI
Connector
AC/DC
Adapter
To CMWrun
(PC)
To Scope
D
D
CLK
D
There are separate A/D converters for each channel that allow for parallel and
fully synchronous data acquisition.
The key characteristics of the probe are the following:
Table 1-2: Technical data
Voltmeter (V) Amperemeter (I) Power (internal mul-
tiplier)
No. of channels 2 or 4 2 or 4 2 or 4
Measurement resolu-
18 bit 18 bit 32 bit
tion
Sampling rate with
5 MSa/s per channel 5 MSa/s per channel 5 MSa/s per channel
R&S RTx
Sampling rate with
R&S CMWrun
50 kSa/s per channel 50 kSa/s per channel 50 kSa/s per channel
(synchronous multiplication of V and I)
For detailed specification and derating information, consider the data sheet.
7User Manual 1326.2139.02 ─ 03
R&S®RT-ZVC
1.3 Unpacking the Instrument
Product Description
Unpacking the Instrument
Figure 1-2: Carrying case (model for R&S CMWrun)
Inspecting the contents
The carrying case contains the following items:
●
Basic voltage and current leads (1), length 16 cm, one lead per each instrument channel
●
USB 3.0 cable (2) (only for R&S CMWrun)
●
Ground cable (3) with 4 mm plugs
●
R&S RT-ZVC probe box (4)
●
Ground clip (5) for connection to the DUT
●
AC power adapter (6) (only for R&S CMWrun)
●
PCB solder-in cables (7):
– Blue and red round 1.02 mm, length 5 cm, one pair per each current chan-
nel
– Blue and red square 0.64 mm, length 5 cm, one pair per each voltage
channel
●
Exchangeable clips for AC power plugs (8) for UK, US, Australian and European standard
8User Manual 1326.2139.02 ─ 03
R&S®RT-ZVC
●
Solder-in contacts (9):
– 8x round headers 1.02 mm
– 4x shorting links, round 1.02 mm, spacing 5.08 mm
●
Blue flat oscilloscope interface cable (10) (only for R&S RTx)
●
User manual
Inspect the package for damage
Keep the package and the cushioning material until the contents have been
checked for completeness and the device has been tested.
If the packaging material shows any signs of stress, notify the carrier and your
Rohde & Schwarz service center. Keep the damaged package and cushioning
material for inspection.
Inspect the product
Product Description
Instrument Overview
If the content is incomplete, damaged, or defect or if the R&S RT-ZVC multi-channel power probe does not operate properly, notify your Rohde & Schwarz service
center.
Calibration certificate
The calibration certificate is not included in the standard shipping. The document
is available for download at https://gloris.rohde-schwarz.com/calcert.
1.4 Instrument Overview
The probe R&S RT-ZVC consists of the following parts:
●
The probe box
●
Leads and accessories for connection to the DUT. See also Chapter 2.3,
"Connecting the Probe to the DUT", on page 22
●
Variant for operation with R&S CMWrun:
AC power adapter and USB 3.0 cable for connection to the PC with
R&S CMWrun application, refer to Chapter 2.2, "Test Setup with
R&S CMWrun", on page 20
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R&S®RT-ZVC
Product Description
Instrument Overview
●
Variant for operation with an oscilloscope:
Blue flat oscilloscope interface cable, refer to Chapter 2.1, "Test Setup with
Oscilloscope", on page 19
The next sections describe the main HW of the probe.
1.4.1 Probe Box
The following section provides an overview of the control elements and sockets of
the probe box and explains how to connect external devices.
Figure 1-3: R&S RT-ZVC: upper, front, and rear view
1 = Status LEDs
2 = ID LEDs
3 = Channel LEDs
4 = Voltmeter sockets
5 = Amperemeter sockets
6 = Ground socket
7 = Socket for AC power adapter
8 = HDMI interface
9 = USB 3.0, micro B socket
LEDs
The status LEDs (1) of the probe box are located in the upper left corner of the
upper plate. They light to indicate the following detections:
●
Power: Probe is on (connected to power supply or R&S RTx).
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R&S®RT-ZVC
●
Scope: Probe is connected with oscilloscope.
●
Trigger: Trigger signal is detected on R&S RTx interface.
●
Overload: Red LED plus blinking affected channel indicate overload at particular voltage or current channel. The overload indication can be reset via a
control dialog.
During an overload at a current channel, the R&S RT-ZVC switches automatically to the next higher range. In case also the 10A range is exceeded, the
amperemeter switches to external shunt mode to protect the probe against
permanent damage. Thus, the current flow through the DUT is interrupted.
In external shunt mode, there is no automated range switching. The user must
take care that the external shunt resistor is not damaged.
Furthermore, there is no automated range switching at voltmeter channels for
overload conditions.
The ID LEDs (2) are located in the middle left part of the upper plate.
●
Probe Z1 to probe Z4: Indicates on which port of the digital extension board
R&S RTx-B1E the probe is attached to.
Product Description
Instrument Overview
Channel LEDs (3) are located in the bottom left corner of the upper plate.
●
I1 to I4: Blue LEDs for up to four current channels. LEDs indicate which channel is enabled in the GUI.
A light-dark flashing indicates active auto-ranging for the corresponding channel (only relevant for variants R&S RT-ZVC04A and R&S RT-ZVC02A).
●
V1 to V4: Green LEDs for up to four voltage channels. LEDs indicate which
channel is enabled in the GUI.
Interfaces
●
2 or 4 sockets (4) for voltage test leads AWG28. Red color at the socket
marks the position of + wire. Number of sockets depends on the instrument
model.
●
2 or 4 sockets (5) for current test leads AWG24. Red color at the socket marks
the position of + wire. Number of sockets depends on the instrument model.
The voltage and current sockets at the probe box are of different type, to avoid
the mixing of voltage and current leads. In addition, current cables have
1.02 mm round pins that allow for currents up to 10 A.
●
Ground socket (6) - to establish common ground with the DUT. For detailed
information on ground connection, refer to Chapter 3.2.1, "Ground Connec-
tion", on page 27.
●
Socket (7) for AC power adapter is used together with the USB interface.
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R&S®RT-ZVC
●
USB 3.0 interface with micro B socket (9) for connection to R&S CMWrun.
●
HDMI socket (8) for blue oscilloscope interface cable to the digital extension
board R&S RTx-B1E of an oscilloscope.
Risk of instrument damage during operation
An unsuitable test setup can damage the instrument and connected devices. When operating the probe together with the oscilloscope, only oscilloscopes of type R&S RTE and R&S RTO2000 must be used.
Amperemeter
The current measurement is performed with a shunt-amperemeter, i.e. the current
measurement is reduced to a measurement of a voltage drop on a resistor where
the current is flowing through. It has digitally adjustable gain. There are three
built-in shunts that can be switched in series to the circuit under test. For using
internal shunts, the circuit under test needs to be interrupted so that the current
can flow through the probe.
Product Description
Instrument Overview
In addition to internal shunts, the amperemeter can work as a sensitive voltmeter
to measure voltage drops on external shunts mounted directly in the circuit under
test (external shunt mode). The maximum input voltage range is 450 mV to GND.
For details, refer to:
●
Chapter 3.3.3, "Internal Shunt Operation", on page 31
●
Chapter 3.3.4, "External Shunt Operation", on page 32
●
Data sheet
Voltmeter
The voltmeter measures both differential and common mode, not floating signals.
The input voltage range is ±15 V to GND. The signal can be attenuated or amplified depending on the selected range. Refer to the data sheet.
Power multiplier (only via USB for R&S CMWrun)
Within the integrated post-processing of R&S RT-ZVC, the internal multiplier uses
the measured values of the voltmeter and amperemeter and provides high precise statistical results. The minimal, maximal, average and RMS current and voltage values are internally calculated with the sampling rate of 5 MSa/s per chan-
12User Manual 1326.2139.02 ─ 03
R&S®RT-ZVC
Product Description
Instrument Overview
nel. The statistical power results (min/max/avg/RMS) are calculated within 32-bit
resolution.
For details, refer to:
●
Chapter 1.2, "Key Characteristics", on page 6
●
Chapter 3.3.2, "Signal Flow for R&S CMWrun Operation (USB IF Only)",
on page 30
1.4.2 Cables and Accessories
The R&S RT-ZVC delivery contains the following cables:
●
Oscilloscope interface cable (only variants for oscilloscopes): blue flat Samtec
Twinax cable
●
USB 3.0 cable with AC power adapter (only variants for R&S CMWrun). USB
cable connects the probe box and the R&S CMWrun controller PC.
AC power supply is required for operation with USB 3.0 interface. Use only
the delivered power adapter.
●
Voltage and current leads for connecting the probe box and the DUT.
Shielded twisted-pair cables are used for the leads. Different accessories for
the signal sockets allow the leads to be connected to a wide range of DUTs,
see Chapter 1.5, "Optional Accessories", on page 14.
– The leads with 2.54 mm square sockets are used for voltage measure-
ments at the DUT. The signal sockets are based on standard 0.64 mm
(25 mil) square pins.
Figure 1-4: Basic lead for voltage measurements
– The leads with 1.02 mm round sockets are used for current measure-
ments. They have a special design to ensure optimal performance for
higher currents. The signal sockets are not compatible to standard accessories based on 0.8 mm (35 mil) round pins.
Figure 1-5: Basic lead for current measurements
●
PCB cables and headers:
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R&S®RT-ZVC
Product Description
Optional Accessories
Figure 1-6: PCB cables, shorting link, header
– The voltage PCB cables are based on standard 0.64 mm (25 mil) square
pins. They are compatible with 2.54 mm square sockets.
– The current 1.02 mm round headers and PCB cables have a special
design optimized for higher currents. Use only either the accessories provided within R&S RT-ZA36 (1333.1911.02), or Special OEM accessories for
current sockets provided by manufacturer as with standard shipping.
Use the delivered shorting links to close unused measurement points at
the DUT for current measurements.
1.5 Optional Accessories
If the included accessories do not meet individual customer requirements, different accessory sets are offered for sale.
Table 1-3: R&S RT-ZA30 (1333.1686.02)
Item Quantity Description
Current lead basic AWG20 (L 32 cm) 2 Extended cable set PCB
Voltage lead basic AWG28 (L 32 cm) 2
Table 1-4: R&S RT-ZA31 (1333.1692.02)
Item Quantity Description
Current lead 4 mm plug AWG20 (L 32 cm) 2 Extended cable set 4 mm
Voltage lead 4 mm plug AWG28 (L 32 cm) 2
Table 1-5: R&S RT-ZA32 (1333.1705.02)
Item Quantity Description
(length 32 cm) for R&S RT-ZVC
(length 32 cm) for R&S RT-ZVC
TRG10R059 AC/DC adapter 10W 6V clips 1 Power adapter for R&S RT-
ZVC
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R&S®RT-ZVC
Product Description
Optional Accessories
Table 1-6: R&S RT-ZA33 (1333.1770.02)
Item Quantity Description
Samtec Twinax flat cable 1 Blue oscilloscope interface
cable
Table 1-7: R&S RT-ZA34 (1333.1892.02)
Item Quantity Description
Current lead 4 mm plug AWG20 (L 100 cm) 2 Extended cable set 4 mm
Voltage lead 4 mm plug AWG28 (L 100 cm) 2
Table 1-8: R&S RT-ZA35 (1333.1905.02)
Item Quantity Description
Current lead basic AWG20 (L 100 cm) 2 Extended cable set PCB
Voltage lead basic AWG28 (L 100 cm) 2
(length 100 cm) for R&S RTZVC
(length 100 cm) for R&S RTZVC
Table 1-9: R&S RT-ZA36 (1333.1911.02)
Item Quantity Description
Adapter cable current to 2.54 mm blue and red* 2x 4 Solder-in cable set for R&S RT-
Current PCB cable AWG20 (L 50 mm) blue and
red
Voltage PCB cable AWG26 (L 50 mm) blue and
red
Solder-in header round 1.02 mm 8
Shorting links 2.54 mm 4
* note the limitations to 3 A for current adapter cable to 2.54 mm
Table 1-10: R&S RT-ZA37 (1337.9130.02)
Item Quantity Description
Current lead BNC female AWG24 (L 160 mm) 1 BNC cable set (length 160 mm)
Voltage lead BNC female AWG28 (L 160 mm) 1
2x 4
2x 4
ZVC
for R&S RT-ZVC
To prepare multiple measurement points on your DUT for connecting the
R&S RT-ZVC probe, the following current connectors are recommended:
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R&S®RT-ZVC
Product Description
Optional Accessories
Table 1-11: Special OEM accessories for current sockets
Item Manufacturer ordering description
Cambion round headers 1.02 mm * 460-3233-02-03-00
Cambion shorting link round 1.02 mm with
5.08 mm spacing *
* as with standard shipping
450-3775-01-06-XX
XX standing for color code
Additional current connector pins (1.02 mm diameter) are available from Cambion
Electronics Ltd.
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R&S®RT-ZVC
Putting into Operation
2 Putting into Operation
The R&S RT-ZVC multi-channel power probe has been designed to withstand a
moderate amount of physical and electrical stress. Treat the probe with care. It
can be damaged if excessive force is applied.
Risk of instrument damage due to mechanical shock
Exercise care to prevent the probe from receiving mechanical shock.
Always handle the probe by the probe cables or probe box.
Avoid putting excessive strain on the probe cable or exposing it to sharp
bends.
Store the probe in a shock-resistant case such as the foam-lined shipping
case that came with the probe.
During operation, the probe slightly heats up. This behavior is normal and not a
sign of malfunction.
Risk of instrument damage due to excess power
Voltages or currents above the specified limits of the R&S RT-ZVC multichannel power probe can damage the probe. Do not exceed the specified
limits.
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R&S®RT-ZVC
Wrist strap with cord
Ground connection
of operational site
Heel strap
Floor mat
Putting into Operation
Damage caused by electrostatic discharge
To avoid damage of electronic components, protect the operational site
against electrostatic discharge (ESD).
Wrist strap with cord
Building ground
Floor mat
Heel strap
Ground connection
of operational site
To protect the operational site, use one or both of the following measures:
●
Wrist strap with cord to ground connection
●
Conductive floor mat and heel strap combination
The following topics are covered in the next sections:
● Test Setup with Oscilloscope.......................................................................... 19
● Test Setup with R&S CMWrun........................................................................ 20
● Connecting the Probe to the DUT...................................................................22
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R&S®RT-ZVC
Putting into Operation
Test Setup with Oscilloscope
2.1 Test Setup with Oscilloscope
A basic test setup with an oscilloscope does not include external power adapter
or USB cable. The connection is realized via the delivered blue flat oscilloscope
interface cable. The R&S RT-ZVC is powered by oscilloscope.
Risk of injury
Connect the oscilloscope to an outlet that has a ground contact.
If grounding is not ensured by the mains system, ground the oscilloscope
using the protective earth conductor on the front panel and an appropriate
cable.
Do not use an isolating transformer to connect the oscilloscope to the AC
power supply.
Supported oscilloscopes are listed in the R&S RT-ZVC data sheet.
The multi-channel power probe variants R&S RT-ZVC04A and R&S RT-ZVC02A
with autoranging are not supported in operation with oscilloscopes.
Figure 2-1: Connecting the probe to the oscilloscope
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R&S®RT-ZVC
Putting into Operation
Test Setup with R&S CMWrun
1. Connect the probe box via oscilloscope interface cable to the HDMI port of
R&S RTx-B1E module at the rear side of oscilloscope. See Figure 2-1.
When the probe is connected to the oscilloscope, the oscilloscope recognizes
the probe and reads out the probe-specific parameters.
2. Configure the active channels and the desired ranges at the oscilloscope
using the ZVC multi-channel power probe dialog under "Vertical".
The procedure depends on the used instrument. For detailed description, refer
to the oscilloscope's user manual.
Risk of instrument damage
To prevent wire damages, do not pull on the cord to disconnect the HDMI
connector from the probe box or oscilloscope. Always grip and pull the connector to disconnect.
2.2 Test Setup with R&S CMWrun
Connect the R&S RT-ZVC multi-channel power probe with the R&S CMWrun as
follows.
Figure 2-2: Test setup with R&S CMWrun
1 = probe box
2 = power adapter
3 = controller computer with R&S CMWrun
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R&S®RT-ZVC
Test Setup with R&S CMWrun
Risk of injury or damage
When operating on the 230V AC power supply, only the supplied AC/DC
wall-mount power adapter of type Cincon TRG10R059-01-23E03 must be
used. To reduce the risk of electric shock, damage of the probe, or unreliable measurement results, do not plug any other type of power adapter into
this product.
To start the measurement, proceed as follows:
1. If not yet done, install the USB driver delivered with R&S CMWrun SW at the
controller PC of R&S CMWrun.
The driver enables the R&S CMWrun application to detect the connected
probe automatically. No additional configuration of probe connection is necessary.
Putting into Operation
2. Connect the probe box via power adapter to the power supply.
3. Connect the probe box via USB cable to the R&S CMWrun controller PC. Use
USB 3.0 port at your PC.
The PC detects the probe as a USB device.
4. For the connection to the DUT, use delivered voltage and current leads and
PCB cables. Refer to Connecting the Probe to the DUT.
5. In the test module "Power Consumption Measurement", specify measurement-specific parameters and input signal characteristics.
The option R&S CMW-KT051 of R&S CMWrun provides the test module
within general-purpose tests.
The characteristics of amperemeter and voltmeter channels must be specified
according to the measured ranges.
6. Start the measurement. Measure current and voltage at the measurement
points of the DUT.
7. Evaluate results within the R&S CMWrun application.
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R&S®RT-ZVC
Putting into Operation
Connecting the Probe to the DUT
2.3 Connecting the Probe to the DUT
To achieve optimum RF performance, the connections have to be always as short
as possible. If long connections cannot be avoided, they have to be preferably
used for the ground socket.
The basic test setup enables up to 4 voltage and up to 4 current measurement
points. The R&S CMWrun supports currently the measurement of only one voltage and one current channel simultaneously at the same time. The following figure shows a test setup with two voltage and two current channels.
Figure 2-3: Test setup
1 = probe box
2 = ground connection
3 = current (I) and voltage (V) leads
It is forbidden to measure own power supply drain of the R&S RT-ZVC at
the AC power supply adapter or at the HDMI connector.
Ground connection
Before starting measurements, establish a common ground between DUT and
probe to keep common voltage within the common mode range of the amplifiers.
Refer to Chapter 3.2.1, "Ground Connection", on page 27.
Ground socket is in the lower right corner of the front plane, refer to Figure 1-3.
You can also clamp the delivered ground clip to your DUT. The clip fits to the
ground socket of the probe using the delivered 4 mm ground cable.
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R&S®RT-ZVC
Connecting the Probe to the DUT
Measurement point connection
The voltage and current leads are connected with the DUT to tap off the measurement signal. Use delivered voltage and current cables. Their connectors fit
into the voltage or current socket of probe box. Red color at the connector marks
the position of + wire. Match the red marks of a connector and socket when plugging a signal lead into the probe box. The correct connector orientation is with the
red mark upward. For details on cables, refer to Chapter 1.4.2, "Cables and
Accessories", on page 13.
To connect the measurement points of the DUT, use solder-in connections. For
details, see Chapter 3.1, "Solder-In Connection", on page 24.
Putting into Operation
23User Manual 1326.2139.02 ─ 03
R&S®RT-ZVC
Measurement Principles
Solder-In Connection
3 Measurement Principles
3.1 Solder-In Connection
To prepare the DUT for measurements, solder the delivered headers or PCB
cables to the DUT, to specify the measurement points.
Headers
The headers soldered to the DUT provide firm
contact with the measurement point during the
whole measurements. The signal lead is plugged onto soldered-in headers on the DUT.
The figure shows headers for current (on the
left) and voltage measurements (on the right).
Standard PCB cables
The PCB cables provide a flexible connection
to the DUT. They are soldered onto the DUT
and connected with the signal lead.
The figure shows PCB cables for voltage (top)
and current measurements (bottom).
24User Manual 1326.2139.02 ─ 03
R&S®RT-ZVC
Shorting links
External shunt
Measurement Principles
Solder-In Connection
If the current measurement points are temporary not connected to the probe box, close the
circuit at the DUT via delivered shorting links.
The figure shows shorting links connected to
soldered-in headers (top) and PCB cables
(bottom) .
To reduce burden voltage, use the external
shunt for the measurements of higher current
drains. The figure shows the solder-in connection of external shunt.
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Adapter PCB current cable to 2.54 mm
Measurement Principles
Signal Integrity
To use the standard square headers also for
current measurements, you can use adapter
cables to 2.54 mm delivered within the option
R&S RT-ZA36, see Table 1-9. The PCB adapters are designed for current measurements of
only up to 3 A. These adapter cables are recommended for external shunt measurements.
With these adapters, the design of sockets
cannot distinguish between the current and
voltage measurement points. Be aware, that
connecting the measurement point of the DUT
to the false probe channel can damage the
DUT.
Risk of instrument damage
Do not exchange the current and voltage connections at the probe box. Be
aware of possible instrument damage.
3.2 Signal Integrity
The R&S RT-ZVC multi-channel power probe transfers the voltage and current of
the electrical signal tapped off the DUT to the post-processing logic. With an ideal
probe, the signal that is post-processed is identical to the input signal at the measurement point of the DUT. The following sections explain, how to minimize signal
alterations.
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Measurement Principles
Signal Integrity
3.2.1 Ground Connection
Connection to earth is established either through USB or scope interface. The
AC/DC wall adapter has no protective earth connector.
In the case of battery operation, the ground of the DUT is floating. High static
potentials between the DUT ground and the probe ground can exceed the operating voltage window of the probe. Therefore it is necessary to connect the ground
socket of the probe to the ground of the DUT. The ground connection also
improves problems with unwanted common mode signals.
Risk of instrument damage and unreliable measurement results
Unsufficient ground connection can damage the internal shunt, cause unreliable measurement results or unexpected high offsets.
Always establish common ground connection and fixed common mode relation even for non-floating DUTs.
Figure 3-1: Ground connection
3.2.2 Electromagnetic Interference
Although shielded twisted-pair cables are used for the leads, the measurement is
highly sensitive to electromagnetic interference effects near the sockets for PCB
cables. Therefore, consider additional shielding methods, such as shield boxes
for the DUT, to avoid interference.
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Measurement Principles
Signal Integrity
3.2.3 Accuracy
The accuracy of power measurements depends on the accuracy of the amperemeter and the accuracy of the voltmeter.
The bandwidth specifies the maximum frequency at which a purely sinusoidal signal is still transferred at 89 % (0.1 dB) of its amplitude. For details, consider the
data sheet.
3.2.4 Dynamic Range and Operating Window
Two separate specifications are necessary to characterize the permissible input
voltage range of a differential voltage probe:
●
The dynamic range (or "differential mode range") designates the maximum differential voltage that can occur between the positive and negative signal pin.
●
At the same time, the two voltage values at each of the two pins - the positive
and negative pin, referenced to the common ground must not exceed a specific limit. This limitation is referred to as the operating voltage window (some
manufacturers also use the term "common mode range" for the same parameter).
If one of these ranges is exceeded, an unwanted signal clipping can occur.
Figure 3-2: Voltage operating window
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The dynamic range between the positive and negative signal pins depends on the
gain or attenuation. The operating voltage window between each of the signal
pins and common ground is not affected by the gain or attenuation.
Signal clipping
Only differential input signals are detected by the probe and displayed.
Common mode signals are suppressed by the probe. Therefore, you possibly do not initially recognize that the operating voltage window is exceeded
owing to inadmissible common mode voltages. If unexpected clipping
occurs, check the positive or negative input voltage relative to ground.
In addition, measuring the common mode input voltage is a convenient way
to detect breaches of the operating voltage window owing to excess DC
common mode voltages.
Measurement Principles
Probing Philosophy
3.3 Probing Philosophy
3.3.1 Signal Flow for Oscilloscope Operation
After the measuring of signal, the R&S RT-ZVC offers the following functions:
●
Deskew: Each signal can be delayed by using the deskew function.
●
Lowpass: To resolve very low voltages and currents, a built-in lowpass module can be activated. The bandwidth reduction affects all channels simultaneously.
●
Decimation: Three different decimation modes can be chosen to reduce the
sample rate to less than 5 MSa/s: "Sample", "Peak detect", and "High Res
Decimation".
●
Trigger: It is possible to set an edge trigger on every voltage or current signal.
The trigger event is transferred to oscilloscope together with the digitized data.
●
The measurement results are transferred via digital interface at maximal sample rate of 5 MSa/s to the oscilloscope for postprocessing.
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I
V
Analog Frontend
Digital Backend (4 in total)
V
I
5 MSa/s
A/D
18 bit
5 MSa/s
A/D
18 bit
5 MSa/s
Decimation
Trigger
Lowpass
Deskew
Figure 3-3: Signal flow with oscilloscope
Measurement Principles
Probing Philosophy
3.3.2 Signal Flow for R&S CMWrun Operation (USB IF Only)
The R&S RT-ZVC multi-channel power probe with integrated post-processing provides high precise statistical results. The minimal, maximal, average and RMS
current and voltage values are internally calculated for 5 MSa/s per channel. The
high measurement resolution is suitable for high accuracy measurements of
instantaneous values.
In contrary, the R&S CMWrun focuses on the long-time battery-life measurements. Therefore, for USB interface, the R&S RT-ZVC performs decimation of
average and peak values provided by post-processing. In the GUI of
R&S CMWrun, specify the decimation level of up to 50 kSa/s for each active
channel.
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I
V
Analog Frontend
X
internal
multiplier
Digital Backend (4 in total)
V
P
I
5 MSa/s
(each channel)
100 KSa/s
(sum to USB)
A/D
18 bit
5 MSa/s
A/D
18 bit
5 MSa/s
Arithmetic's
(min, max, avg, RMS)
Decimation
Figure 3-4: Signal flow with R&S CMWrun
Measurement Principles
Probing Philosophy
3.3.3 Internal Shunt Operation
Before measurements, the correct measurement range has to be specified in the
settings. Therefore, the amperemeter provides internal shunts (2) of 10 kΩ, 10 Ω,
and 10 mΩ to be selected as a reference resistor.
I
x
7
6
Figure 3-5: Scheme of the shunt-amperemeter with internal shunt
1 = R&S RT-ZVC probe, channel x
2 = selectable internal shunts
3 = switch for shunt selection
4 = fuse, 15 A (non-resettable)
5 = current leads - shielded twisted pair
6 = DUT
7 = DUT's power supply
5
3
4
2
V
1
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Measurement Principles
Probing Philosophy
With the internal shunt selection, the operating range of the amperemeter is
specified. At the same time, the burden voltage at the amperemeter input can be
estimated.
The burden voltage is the DUT circuit loading caused by leads, connectors and
the amperemeter circuit. For values of the total round-trip resistance that can be
seen at the test lead ends, consider the data sheet. For instance, the total resistance for the basic current leads AWG24 (5) contained in the standard shipping is
128 mΩ nominal.
3.3.4 External Shunt Operation
The burden voltage depends on the operating range of amperemeter. Regarding
the shunt selection, i.e. the burden voltage level, there is a trade-off between the
burden of the circuit under test and the SNR at the front-end input. From the DUT
perspective, the burden voltage has to be kept low not to distort the device operation. In contrast, from the probe’s view the voltage has to be as large as possible
to obtain a good SNR. For that reason, the external shunt can be applied to get
the best compromise of both for a specific measurement range.
3
5
8
7
6
Figure 3-6: Scheme of the shunt-amperemeter with external shunt
1 = R&S RT-ZVC probe, channel x
4 = fuse, 15 A (non-resettable)
5 = current leads - shielded twisted pair
6 = DUT
7 = DUT's power supply
8 = external shunt to reduce burden voltage
4
V
1
For higher current values, a significant burden voltage appears at the amperemeter connectors. For current values above approximately 3 A, an external shunt (8)
is recommended. Consider also maximal tolerable voltage drop of the DUT. By
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selecting an external shunt, the amperemeter becomes a sensitive voltmeter and
allows you to measure the current over a voltage drop.
Requirements of external shunt
For high-current measurements, the use of external shunts directly mounted in
the circuit under test is preferred regarding the burden voltage issue.
There are different requirements the low-value (for example ≤10 mΩ) shunt resistor has to fulfill:
●
High-power rating of ≥1 W (depending on actual current and resistor value)
●
High precision (low-resistance tolerance) of ±0.5% or lower
●
Low temperature coefficient, ≤25 ppm/°C
●
Four terminals (Kelvin connections) for precise and accurate measurements
To fulfill these requirements, precise metal strip resistors are recommended, such
as Vishay CSM series. The 10 mΩ shunt in the probe is of type CSM3637 (Vishay
Y14880R01000B9R). The smallest shunt available in this series is 1 mΩ.
Measurement Principles
Probing Philosophy
3.3.5 Autoranging Mode
For the multi-channel power probe variants R&S RT-ZVC04A or R&S RTZVC02A, auto-ranging mode can be enabled on request either on internal or
external shunts.
Auto-Ranging is performed by gain-switching according to the measured values,
as illustrated in the following figure. Thus, switching times are kept low and the
burden voltage seen by the DUT is not affected. Only if there is an overload, the
R&S RT-ZVC switches automatically to the next smaller shunt (or external shunt
mode) to protect the probe against permanent damage.
The auto-ranging mode allows seamless current measurements of up to 50
ksample/s.
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Range
e.g. 1Ω
= Seamless range change
900 mA
225 mA
22.5 mA
2.25 mA
Seamless range changes
Sleep
Idle
Activity
Measurement Principles
Probing Philosophy
Figure 3-7: Seamless ranging
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Maintenance and Service
Cleaning
4 Maintenance and Service
4.1 Service Strategy
Like all Rohde & Schwarz devices, Rohde & Schwarz probes are of high quality
and require only minimum service and repair. However, if the probe needs to be
serviced, contact your Rohde & Schwarz service center. Return a defective probe
to the Rohde & Schwarz service center for diagnosis and exchange.
You can return the R&S RT-ZVC multi-channel power probe for calibration. The
service personnel performs the required tests.
4.2 Returning the Probe for Servicing
Use the original packaging to return your Rohde & Schwarz probe to your
Rohde & Schwarz service center.
If you cannot use the original packaging, consider the following:
1. Use a sufficiently sized box.
2. Protect the probe from damage and moisture (e.g. with bubble wrap).
3. Use some kind of protective material (e.g. crumpled newspaper) to stabilize
the probe inside the box.
4. Seal the box with tape.
5. Address the package to your nearest Rohde & Schwarz service center.
4.3 Cleaning
To clean the exterior of the probe, use a soft cloth moistened with either distilled
water or isopropyl alcohol. Before using the probe again, make sure to dry it completely.
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Device damage caused by cleaning agents
Cleaning agents contain substances that can damage the device; for example, solvent can damage the labeling or plastic parts.
Never use cleaning agents such as solvents (thinners, acetone, etc.), acids,
bases or other substances.
Device damage caused by static electricity
Before cleaning the facing surfaces of the sensor head, discharge any static
electricity at your hands. Thus you ensure that a high voltage caused by
static electricity is not applied to the device. Application of a high voltage to
the device can damage the internal Hall elements or circuitry. Static electricity at your hands can have built up by touching a nearby metal object.
Maintenance and Service
Discarding the Probe
4.4 Calibration Interval
The recommended calibration interval for R&S RT-ZVC multi-channel power
probe is one year for highest accuracy and two years for general test and measurement applications. For servicing, send the probe to your nearest
Rohde & Schwarz service center (see Chapter 4.2, "Returning the Probe for
Servicing", on page 35).
4.5 Discarding the Probe
Handle and dispose the probe in accordance with local regulations.
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Index
Index
A
AC/DC adapter
Caution ............................................... 21
Accessories
Usage ................................................. 24
Accuracy ..................................................28
Adapter for current PCB cable to 2.54 mm
Solder-in connection ........................... 26
C
Cleaning .................................................. 35
Common mode range ..............................28
Compatibility ..............................................5
Connecting to DUT ..................................22
Connecting to R&S RTx .......................... 19
D
Differential input voltage ..........................29
Dynamic range ........................................ 28
E
External shunt
Solder-in connection ........................... 25
G
R&S RT-ZA32 .......................................... 14
R&S RT-ZA33 .......................................... 15
R&S RT-ZA34 .......................................... 15
R&S RT-ZA35 .......................................... 15
R&S RT-ZA36 .......................................... 15
R&S RT-ZA37 .......................................... 15
S
Sampling rate ............................................ 7
Service .................................................... 35
Signal integrity .........................................26
T
Test setup ................................................ 20
U
Unpacking ................................................. 8
Use cases ..................................................5
Using headers
Solder-in connection ........................... 24
Using PCB cables
Solder-in connection ........................... 24
Using shorting links
Solder-in connection ........................... 25
Ground connection .................................. 27
M
Maintenance ............................................35
Measurement resolution ............................7
O
OEM accessories for current sockets ......16
Operating voltage window ....................... 28
P
Probe
Calibration ...........................................36
Cleaning ..............................................35
Connection ....................................19, 20
Returning ............................................ 35
Product description ....................................5
R
R&S RT-ZA30 .......................................... 14
R&S RT-ZA31 .......................................... 14
37User Manual 1326.2139.02 ─ 03
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