Analog Input Disconnect Detect - Hitachi WJ200 Series Instruction Manual

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Analog Input Disconnect Detect

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
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 value, the [Dc] output turns OFF. There is no error condition to clear.
B082
Option Terminal
Code Symbol
ODc
27
OIDc
28
Valid for inputs:
Required settings
Notes:
• The [Dc] output can indicate an analog signal
disconnect when the inverter is in Stop Mode, as
well as Run Mode.
• The 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.
Function Name State
Analog voltage Input
Disconnect Detect
Analog current Input
Disconnect Detect
11, 12, AL0 – AL2
A001=01, B082
is the Start Frequency
B082
ON when signal loss is detected on [O] input
OFF when no signal loss is detected on [O] input
ON when signal loss is detected on [OI] input
OFF when no signal loss is detected on [OI] input
Example for terminal [11] (default output
configuration shown – see
Inverter output
terminal circuit
Example for terminal [AL0], [AL1], [AL2] (requires
output configuration – see
Inverter logic
circuit board
See I/O specs on
Description
page 3-90):
DC
CM2 11
RY
page 4-52 and 3-90):
DC
AL0 AL1 AL2
Power
Load
supply
page 4-6