EM-M22 is a True RMS signal converter designed for AC current measurement using a current transformer. It accepts the standard 1 A and 5 A secondary-current ranges commonly used in current-transformer applications.
The measured AC current is converted into a standard 4–20 mA process signal. The output circuit is powered from the current loop, so no separate auxiliary supply is required.
The EM-M22 measures the effective RMS value of the current-transformer secondary signal. True RMS measurement enables the converter to process both sinusoidal and non-sinusoidal current waveforms within the specified operating limits.
The supported measuring-frequency range is 45 Hz to 1 kHz.
Two measuring ranges are provided for standard current-transformer secondary currents:
The 1 A range has a specified input impedance of 0.27 Ω. The 5 A range has a specified input impedance of 0.05 Ω.
The measured current is converted into a proportional 4–20 mA output signal. The output loop operates from a 12–32 VDC supply and provides the operating power required by the converter.
With a 24 VDC loop supply, the specified maximum loop resistance is 700 Ω.
The 4–20 mA output can also be converted into a 1–5 V signal by connecting a suitable resistor according to the connection diagram.
A 250 Ω conversion resistor produces a nominal voltage of 1 V at 4 mA and 5 V at 20 mA.
The EM-M22 includes protection against incorrect connections and voltage transients.
| Output-loop supply voltage | 12–32 VDC |
|---|---|
| Measurement principle | True RMS |
| AC current range 1 | 0–5 A RMS |
| Peak current, 5 A range | 20 A peak |
| Input impedance, 5 A range | 0.05 Ω |
| AC current range 2 | 0–1 A RMS |
| Peak current, 1 A range | 4 A peak |
| Input impedance, 1 A range | 0.27 Ω |
| Current output | 4–20 mA |
| Optional voltage output | 1–5 V using a conversion resistor |
| Linearity error | < 0.5% with a sinusoidal input |
| Thermal drift | < 200 ppm/°C |
| Settling time | 0.3 s |
| Measuring-frequency range | 45–1000 Hz |
| Maximum loop resistance | 700 Ω with a 24 VDC loop supply |
| Operating ambient temperature | 0 … +50 °C |
Ordering larger quantities +100pcs.
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