Multi-functional Receiving and 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 CM7291 is the wireless receiving/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.
By connecting an AC/DC current sensor to the Display Unit CM7291, and then the system 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)
Select from an extensive lineup of sensors designed for various applications. AC/DC auto-zero current sensors are ideal for long-term recording.
Send measurement data to a smartphone or tablet using Bluetooth® wireless technology and use the GENNECT Cross dedicated app to display and review measured values and waveforms in real time.
The software provides a range of functionality that helps manage data in the field, including photographing measurement sites, placing measurement results on photographs, and saving hand written memos.
System:
Display Unit CM7291
AC/DC Auto-zero Current Sensor CT7731
Output Cord L9095
Memory HiCorder MR8870
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 CM7291 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 CM7291’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 CM7291 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 CM7291 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 CM7291 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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| Communication interface | Built in Bluetooth® 4.0 LE, Display of measured values on an iOS or Android handset (CM7291 only) | |||||
| 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 (*1) | 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 | |||||
| Countries and regions where wireless operation is currently supported | Australia, Austria, Bangladesh, Belgium, Bulgaria, Canada, Chile, Colombia, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Georgia, Germany, Greece, Hong Kong, Hungary, Iceland, Ireland, Israel, Italy, Japan, Kenya, Korea, Latvia, Liechtenstein, Lithuania, Luxembourg, Macao, Malta, Myanmar, Netherlands, New Caledonia, New Zealand, Norway, Peru, Poland, Portugal, Romania, Saudi Arabia, Singapore, Slovakia, Slovenia, Spain, Sweden, Switzerland, Thailand, Turkey, United Kingdom, United States, Viet Nam | |||||
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| Note | Use of devices that emit radio radiation requires approval in the country of use. Thus, use of the instrument in a country or region where they have not been approved may be subject to penalty as a violation of law. | |||||
