Analog Input Disconnection Detection - Omron 3G3MX2 User Manual

Using Intelligent Output Terminals

4-6-19 Analog Input Disconnection Detection

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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 indi-
cate a signal loss condition.
Current signal loss at [OI] terminal – The [OI] terminal accepts a 4 mA to
20 mA signal, with 4 mA representing the beginning of the input range. If the
input current falls below 4 mA, 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
error condition to clear.
Option Terminal
Code Symbol

ODc Analog O
disconnec-
tion detec-
tion

OIDc Analog OI
disconnec-
tion detec-
tion
Valid for inputs: 11, 12, AL0 - AL2
=, 
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.

value, the [Dc] output turns OFF. There is no
Function State
Name
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
Section 4-6

is the Start Frequency
Description