4
Reliably capture waveform anomalies buried within normal signals
- Memory (Digital Oscilloscope) Function -
Memory Function for High-Speed Waveform Monitoring
A/D
Isolation
Using the same operating principle as a digital oscilloscope, data is recorded
to the expanded internal memory at high speed. Sampling rate is up to 20 MS/s
(50-ns period) for all channels simultaneously. Capture unpredictable operating
anomalies and transient waveforms.
conversion
Input signal
Display
Thermal Printer
Write on
memory
A/D
conversion
Isolation
n Records to Solid-State Memory
Input signal
Because instruments that rely on disk access such as hard disk drives are
susceptible to vibration, they are often unsuitable for on-board measurements.
MEMORY HiCORDERs are preferable for on-board testing because they write
data to solid-state memory with no moving parts. You can back up data to a
PC Card or USB storage device when finished measuring. When the optional
memory backup unit is installed, the instrument’s internal memory data is
preserved when power is turned off.
Sampling period
Time
Output waveform
n All Channels Isolated, 20 MS/s Sampling
n Large Capacity Internal Memory
Except when using the Scanner Module, every input channel has its
own A/D converter. Because all channels are sampled simultaneously,
transient waveforms can be easily observed along with signals. The
Scanner Module switches all inputs through a single A/D converter,
but even in that case, all channels are isolated.
Both high-speed write capability and a large memory capacity are
provided to support high-speed sampling. Total memory capacity
ranges from 32 megawords to 1 gigaword, enabling capture of
waveform peaks by high-speed sampling, as well as long-term
recording and long-period waveform capture. (Model 8861-50 provides twice the
memory capacity, but with the same recording time limits.)
n External Sampling Input Capability
n Internal Memory Division (Segmentation) Function
Internal memory can be segmented for use into 4,096 blocks. By
using “sequential save” to write data to the segmented memory, the
waveform in any block can be overlaid with that in a reference block
for comparison.
The sampling rate for memory recording can be synchronized to an
external clock signal (up to 10 MS/s). So, for example, sampling can be
synchronized to the rotation cycle of an engine.
n
An Actual Waveform
Measurement Example
For operational analysis of an inverter, the waveforms of the high
frequency switched carrier and the low frequency fundamental
both need to be observed. High-speed sampling, long-term memory
recording and input isolation make these observations possible.
Various HIOKI non-contact clamp-on sensors capable of measuring up
to HF ranges can be used to observe current waveforms.
CLAMP ON PROBE ꢁꢀ70 Series provides flat electrical
characteristics for observing current waveforms over a
remarkably broad range of amplitudes from mA order to
500 A at frequencies from DC to HF.
n High-Voltage
Measurement
HIGH VOLTAGE UNIT 8961
Measuring in situations where high voltage exists between channels,
such as three-phase inverters, requires a measurement instrument that
has all input channels isolated. In addition, when measuring signals
such as those of switching circuits that include common-mode voltage
with a high-frequency component, the isolated circuit’s common-mode
frequency rejection characteristics can greatly affect measurements.
To measure these kinds of voltages, you can use the HIGH VOLTAGE
UNIT 8961 or the optional DIFFERENTIAL PROBE 9ꢁꢀꢀ for CAT III
600-volt AC and DC maximum ratede voltage to earth.
DIFFERENTIAL PROBE 9322
Three-Phase Inverter Output Circuit
(Because emitter voltage for each phase is different, isolated measurements are essential.)
ASM-SENSOR [ ASM GMBH ]
