Hitachi CP-X200 instruction manual －46, Analog Input Disconnect Detect

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Analog Input Disconnect Detect

and

This feature is useful when the inverter receives a speed reference from an external device. Upon input signal loss at either the [O] or [OI] terminal, the inverter normally just decelerates the motor to a stop. However, the inverter can use the intelligent output terminal [Dc] to signal other devices that a signal loss has occurred.

Voltage signal loss at [O] terminal - Parameter B082 is the Start Frequency Adjustment. It sets the beginning (minimum) output frequency when the speed reference source is greater than zero. If the analog input at terminal [O] is less than the Start Frequency, the inverter turns ON the [Dc] output to indicate a signal loss condition.

Current signal loss at [OI] terminal - The [OI] terminal accepts a 4mA to 20mA signal, with 4mA representing the beginning of the input range. If the input current falls below 4mA, the inverter applies a threshold to detect signal loss.

Note that a signal loss is not an inverter trip event. When the analog input value is again above the B082 value, the [Dc] output turns OFF. There is no error condition to clear.

Option	Terminal	Function Name	State	Description
Code	Symbol
06	Dc	Analog Input	ON	when the [O] input value < B082 Start Frequency
		Disconnect Detect		Adjustment (signal loss detected), or when the [OI
				input current is less than 4mA
			OFF	when no signal loss is detected

		Monitoring
Operations and	Operations
	Monitoring

Valid for inputs:	11, AL0 – AL2
Required settings	A001=01, B082

Notes:

ξThe [Dc] output can indicate an analog signal disconnect when the inverter is in Stop Mode, as well as Run Mode.

ξThe example circuit for terminal [11] drives a relay coil. Note the use of a diode to prevent the negative-going turn-off spike generated by the coil from damaging the inverter’s output transistor.

Example for terminal [11] (default output configuration shown – see page 3-54):

Inverter output
terminal circuit		Dc
	CM2		11

RY

Example for terminal [AL0], [AL1], [AL2] (requires output configuration – see page 4-35 and 3-54):

Inverter logic		Dc
circuit board
	AL0	AL1	AL2
	Power		Load
	supply

See I/O specs on page 4-6