Display and Output Unit for the CT7600 and CT7700 Series AC/DC Current Sensors
DISPLAY UNIT CM7290
Description
Model No. (Order Code)
| CM7290 | For the CT7000 series |
|---|
Note: CM7290, CM7291 cannot be used alone. Use with CT7600 series, CT7700 series, or CT7040 series.
Hioki clamp on meters are best-in-class measuring devices incorporating Hioki’s expertise in current sensing technology. The CM7290 is the display and output unit for the CT7600 and CT7700 AC/DC Current Sensor series, creating a standalone clamp meter for field use or enabling waveform signals to be output to a Hioki memory recorder or logger for further analysis.
Key Features
• Power supply and signal output for Current Sensor CT7600, CT7700, CT7040 series
• Simultaneous dual display of the measured values, frequency, and output rate
• Four output formats to output data to loggers or other devices (via Display Unit)
• Supports AC adapter, AA alkaline batteries, and external power supply
Current Measurement Using an AC/DC Current Sensor: Basic Measurement Settings
By connecting an AC/DC current sensor to the Display Unit CM7290 and the Display Unit to a data logger or Memory HiCorder, you can output:
• A DC or AC (up to 5 kHz/10 kHz) current waveform as-is (using WAVE mode for waveform output)
• An analog signal generated by converting the input waveform to a series of RMS values (using RMS mode for RMS output)
• An analog signal generated by detecting the current waveform’s peak value (using PEAK mode for peak output
• An analog waveform generated by detecting the frequency of the current waveform (using FREQ mode for frequency output)
Current Measurement Using an AC/DC Current Sensor: Compatible Current Sensors
You can use any of a selection of available AC/DC current sensors with ratings ranging from 100 A to 2000 A. The CM7290 supports two types of current sensor: AC/DC Auto-zero Current Sensors, which have a sensor frequency band ranging from DC to 5 kHz AC, and AC/DC Current Sensors, which have a frequency band ranging from DC to 10 kHz AC.
Current Measurement Using an AC/DC Current Sensor: Auto-Zero Current Sensor Functionality
Because temperature variations cause the zero-point to shift when using a conventional DC current sensor to measure DC current, it is necessary to perform zero-adjustment periodically when recording data over an extended period of time with such a sensor. This shortcoming is caused by the effects of the Hall element that conventional DC current sensors use to to detect current. Hioki’s new auto-zero current sensors incorporate a new switching-based offset cancellation circuit developed to address this problem. The new design minimizes zero-point shift, making it possible to record DC current values over an extended period of time without the need for periodic zero-adjustment.
Current Measurement Using an AC/DC Current Sensor: WAVE Waveform Output Function
The Display Unit CM7290 converts the current waveform for current flowing in a wire to which an AC/DC current sensor has been applied to a proportional voltage signal. By inputting that signal to a digital oscilloscope or Memory HiCorder, you can measure instantaneous AC or DC current waveforms such as a motor’s starting current waveform. Alternatively, by using the CM7290’s WAVE waveform output function in combination with a data logger, you can observe the DC current generated by a PV system’s solar panels over extended periods of time. Auto-zero current sensors are ideally suited to applications in which a DC current must be observed over an extended period of time.
Current Measurement Using an AC/DC Current Sensor: RMS Mode for RMS Output
In this mode, the Display Unit CM7290 converts the current waveform for current flowing in a wire to which an AC/DC current sensor has been applied to a series of RMS values. It then outputs the result as a voltage signal (FAST: 45 Hz or greater, NORMAL: 10 Hz or greater, SLOW: 3 Hz or greater). This configuration is ideally suited to applications such as AC current measurement on the power supply side of a welding machine, which is characterized by abrupt current fluctuations, or long-term measurement of RMS values for the current waveform from an inverter operating at varying frequencies or a machine tool’s spindle motor.
Current Measurement Using an AC/DC Current Sensor: PEAK Mode for Peak Output
In this mode, the Display Unit CM7290 detects the peak value of the current waveform for current flowing in a wire to which an AC/DC current sensor has been applied at the rate of 2 kS/s (= 500 μs). It then outputs its absolute value as a voltage signal with an output refresh time of 0.02 s (FAST), 0.2 s (NORMAL), or 1 s (SLOW). This configuration is ideally suited to applications in which the maximum current value of a rapidly fluctuating power supply line or load must be continuously recorded.
Current Measurement Using an AC/DC Current Sensor: FREQ Mode for Frequency Output
In this mode, the Display Unit CM7290 calculates the frequency of the current waveform for current flowing in a wire to which an AC/DC current sensor has been applied at the user-specified interval. It then outputs the result as a voltage signal with an output refresh time of 0.2 s (FAST), 0.2 s (NORMAL), or 3 s (SLOW). In this configuration, the CM7290 can be used in applications such as frequency fluctuation inspections and testing of compressors and motors.
Basic specifications (Accuracy guaranteed for 3 years, Post-adjustment accuracy guaranteed for 3 years)
| Sensor | CT7642, 7742 | CT7636, 7736 | CT7631, 7731 |
|---|---|---|---|
| Measurement parameters | DC, AC, DC+AC, Hz | ||
| Crest factor | 3 at 5000 count or 2.5 at 6000 count for AC and DC+AC | ||
| Output method | WAVE, RMS, PEAK, FREQ | ||
| Input connectors | HIOKI PL 14 | ||
| Output update time | PEAK--- FAST: 0.02 s / NORMAL: 0.2 s / SLOW: 1 s FREQ--- FAST: FAST: 0.2 s / NORMAL: 0.2 s / SLOW: 3.0 s (WAVE, RMS: analog output) | ||
| PEAK sensing duration | 2 ms or greater (during PEAK MAX/PEAK MIN and PEAK output) | ||
| Other functions | Auto range, Zero adjustment at power-up, Analysis display, Filter, Output amplification, Display value hold, Backlight , Auto-power save, Save settings, keypad lock | ||
| Typical accuracy (WAVE output DC) | ±2.0% rdg. ±10.8 mV (60.00 A range) | ±2.5% rdg. ±30.8 mV (60.00 A range) | ±1.5% rdg. ±5.8 mV (60.00 A range) |
| Typical accuracy (RMS output AC) | ±2.3% rdg. ±10.8 mV (60.00 A range) | ±2.8% rdg. ±30.8 mV (60.00 A range) | ±1.8% rdg. ±5.8 mV (60.00 A range) |
| Power supply | LR6 alkaline batteries (AA) ×2, Continuous use: 16 h (backlight OFF and WAVE or RMS output, when used with CT7600s), Rated power 2.5 VA or AC adapter 9445-02/03 (100 to 240V AC), or 5 to 15 V DC external power supply, Rated power 2.5 VA | ||
| Dimensions and mass | 52 mm (2.05 in)W × 163 mm (6.42 in)H × 37 mm (1.46 in)D, 220 g (7.8 oz) (including protector and battery) | ||
| Accessories | LR6 alkaline batteries ×2, Protector ×1, Instruction manual ×1 | ||
Options
AC/DC current input
EXTENSION CABLE L0220-03
10 m (32.81 ft) length
EXTENSION CABLE L0220-02
5 m (16.41 ft) length
EXTENSION CABLE L0220-01
2 m (6.56 ft) length
AC/DC CURRENT SENSOR CT7631
・ DC to 10kHz (-3dB) ・Rated 100 A AC/DC ・ 1mV/A output ・φ 33 mm (1.30 in) core dia.
AC/DC AUTO-ZERO CURRENT SENSOR CT7742
・ DC to 5 kHz (-3dB) ・ Rated 2000 A AC/DC ・φ 55 mm (2.17 in) core dia.
AC/DC AUTO-ZERO CURRENT SENSOR CT7736
・ DC to 5 kHz (-3dB) ・ Rated 600 A AC/DC ・φ 33 mm (1.30 in) core dia
AC/DC AUTO-ZERO CURRENT SENSOR CT7731
・ DC to 5 kHz (-3dB) ・ Rated 100 A AC/DC ・ φ 33 mm (1.30 in) core dia.
AC/DC CURRENT SENSOR CT7642
・ DC to 10kHz (-3dB) ・Rated 2000 A AC/DC ・ 0.1mV/A output ・φ 55 mm (2.17 in) core dia.
AC/DC CURRENT SENSOR CT7636
・ DC to 10kHz (-3dB) ・Rated 600 A AC/DC ・ 1mV/A output ・φ 33 mm (1.30 in) core dia.
Current Input 2000A AC/DC
* The CT9920 is necessary for connecting the current sensor with HIOKI PL14 to the PW3390
AC/DC AUTO-ZERO CURRENT SENSOR CT7742
・ DC to 5 kHz (-3dB) ・ Rated 2000 A AC/DC ・φ 55 mm (2.17 in) core dia.
AC/DC CURRENT SENSOR CT7642
・ DC to 10kHz (-3dB) ・Rated 2000 A AC/DC ・ 0.1mV/A output ・φ 55 mm (2.17 in) core dia.
Current Input 6000A
* The CT9920 is necessary for connecting the current sensor with HIOKI PL14 to the PW3390