Hitachi L200 Notes:, Analog Input Disconnect Detect, Voltage signal loss at [O] terminal, Current signal loss at [OI] terminal

4–44

Using Intelligent Output Terminals

Analog Input Disconnect Detect

Operations and Monitoring

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 machinery that a signal loss has occurred.

Voltage signal loss at [O] terminal - Parameter B082 is the Start Frequency Adjust- ment. 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

Output

Description

Code

Symbol

State

06

Dc

Analog Input

ON

when the [O] input value < B082 Start

Disconnect Detect

Frequency Adjustment (signal loss detected), or

when the [OI input current is less than 4mA

OFF

when no signal loss is detected

Valid for outputs:

11, 12, AL0 – AL2

Example (requires output configuration—

see page 3–47):

Required settings:

A001=01, B082

Inverter output

Dc

Notes:

terminal circuit

• The [Dc] output can indicate an analog signal

disconnect when the inverter is in Stop Mode, as

CM2

12

11

well as Run Mode.

• The example circuit for terminal [12] drives a relay

coil. Note the use of a diode to prevent the negative-

+

RY

going turn-off spike generated by the coil from

–

damaging the inverter’s output transistor.

Example for terminals [AL0], [AL1], [AL2]

(requires output configuration—

see pages 4–35 and 3–47):

Inverter logic

Dc

circuit board

		AL0	AL1		AL2
	Power
See I/O specs				Load
	supply
on page 4–6.