Hitachi L2002 - Manual (Page 189)

L200
2
Inverter
Oper
ations
and Monitor
ing
4–45
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 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
Code
Terminal
Symbol
Function Name
Output
State
Description
06 Dc Analog Input
Disconnect Detect ON when the [O] input value < B082 Start
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
Required settings: A001=01, B082
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 [12] 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.
RY
+
–
Example (requires output configuration—
see page
3–54 ):
Inverter output
terminal circuit Dc
Example for terminals [AL0], [AL1], [AL2]
(requires output configuration—
see pages
4–36 and 3–54 ):
AL0 AL2 AL1
Inverter logic
circuit board
See I/O specs
on page
4–6 .
Dc
Load
Power
supply
12 11 CM2