One sensor is connected per channel:
The sensor interface of the module can only be configured for MPU sensors.
The minimum signal detection value for MPU sensor can be configured by setting the parameter MPU input Mode to one of the following modes:
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In Sensitive mode, the minimum signal detection value is 0.3 V peak to peak.
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In Noisy mode, the minimum signal detection value is 2.8 V peak to peak.
MPU Broken Wire Detection
The module can return random frequency values or zero in case of wrong connection with the MPU sensor. The COUNTER_STATUS bit VALIDITY_FREQUENCY is false in both cases.
In addition, when the MPU broken wire detection is configured, the module can detect the wrong connection of an MPU sensor while a random frequency or zero frequency is measured. The MPU broken wire detection returns a fault when not detecting the normal condition as for an MPU sensor properly connected.
The parameter MPU input Mode must be set in Sensitive mode when using the MPU broken wire detection and the connected MPU sensor must satisfy the following characteristic table:
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Expected characteristic
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Value
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From
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Serial self
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Minimum 10 mH
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Internally to the MPU sensor
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Serial resistor
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Minimum 150 Ω
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Internally to the MPU sensor
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Parallel resistor
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Minimum 2 kΩ
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Optional signal resistor
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Parallel capacitor
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Maximum 3 nF
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Cable from sensor to the terminal block
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Setting the parameter MPU Line detection to With for sensors with other characteristics can give an unexpected detection error.
Fast frequency changes from pulse to pulse must be avoided when using the MPU broken wire detection. However when those variations are corrected using the pattern recognition, the broken wire detection can be used.
CAUTION 