Hitachi WJ200-001L, Instruction Manual

Page: 281 / 680

4

74
Communication signal Disconnect Detect
This signal function is enabled only when ModBus-RTU has been selected for the
communication. If a reception timeout occurs, the inverter continues to output the
communication line disconnection signal until it receives the next data.
Specify the limit time for reception timeout by setting the communication trip time
(

).
Option
Code
Terminal
Symbol
Function Name State Description

NDc Communication
signal disconnect
detection ON When there is a disconnection in communiciation
OFF When there is no disconnection in communiciation
Valid for inputs:
11, 12, AL0
– AL2
Example for terminal [11] (default output
configuration shown
– see
page 3-89 ):
Example for terminal [AL0], [AL1], [AL2] (requires
output configuration
– see
page 4-51 and 3-91 ):
See I/O specs on
page 4-6
Required settings

Notes:

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.
External control equipment
Communication
trip time

Monitoring timer
Communication line
disconnection signal (NDc)
RY
Inverter output
terminal circuit
CM2 11
NDc
AL1
Power
supply
Load
AL0 AL2
Inverter logic
circuit board NDc