A-Err Analog Input Current Loop fault in Toshiba drive
A-Err Analog Input Current Loop Error fault in Toshiba drive
Description "A-Err" is similar to "Loss of AI" but specifically indicates a "Current Loop" break on the 4-20mA input. The drive expects a closed circuit. If the circuit opens (0mA), the voltage at the input terminal floats or drops to a level that indicates a physical wire break rather than just a 0% signal. Causes
1. Transmitter Failure: The pressure/flow sensor sending the 4-20mA signal has lost power.
2. Cut Wire: Field wiring is severed.
3. Burden Resistor: If the drive requires an external 250-ohm resistor for current inputs (older models), the resistor may be blown or missing.
4. Software Config: The parameter is set to "4-20mA" (where 4mA is min), but the source is sending "0-20mA" (where 0mA is valid). The drive sees 2mA and assumes a broken wire. Solution Measure the current on the input loop with a multimeter (series connection).
- If 0mA: The loop is broken. Check the sensor and power supply. - If 4mA+: The signal is good. Check the drive parameter F201/F202. Ensure the "Signal Loss Level" is not set too high.
If you want to disable this check (e.g., during commissioning), set the "Analog Input Signal Loss" action to "None" or decrease the detection threshold to 0%.
Description "A-Err" is similar to "Loss of AI" but specifically indicates a "Current Loop" break on the 4-20mA input. The drive expects a closed circuit. If the circuit opens (0mA), the voltage at the input terminal floats or drops to a level that indicates a physical wire break rather than just a 0% signal. Causes
1. Transmitter Failure: The pressure/flow sensor sending the 4-20mA signal has lost power.
2. Cut Wire: Field wiring is severed.
3. Burden Resistor: If the drive requires an external 250-ohm resistor for current inputs (older models), the resistor may be blown or missing.
4. Software Config: The parameter is set to "4-20mA" (where 4mA is min), but the source is sending "0-20mA" (where 0mA is valid). The drive sees 2mA and assumes a broken wire. Solution Measure the current on the input loop with a multimeter (series connection).
- If 0mA: The loop is broken. Check the sensor and power supply. - If 4mA+: The signal is good. Check the drive parameter F201/F202. Ensure the "Signal Loss Level" is not set too high.
If you want to disable this check (e.g., during commissioning), set the "Analog Input Signal Loss" action to "None" or decrease the detection threshold to 0%.
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