Multi-functional Receiving/Display Unit to Use Right on the Field or Output to Advanced Recorder or Logger
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.
| CM7290 | For the CT7000 series |
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Select from an extensive lineup of sensors designed for various applications. AC/DC auto-zero current sensors are ideal for long-term recording.
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)
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.
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.
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.
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.
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.
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.
| Sensor | CT7642, 7742 | CT7636, 7736 | CT7631, 7731 | |||
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| 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) |
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| PEAK sensing duration | 2 ms or greater (during PEAK MAX/PEAK MIN and PEAK output) |
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| 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) |
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| 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) |
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| 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 |
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| Dust and water resistance * | IP54 (with sensor connected and caps fitted to AC adapter and power connector) | |||||
| 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) | |||||
| Included accessories | LR6 alkaline batteries ×2, Protector ×1, Instruction manual ×1 | |||||
