Communication Line Disconnection Signal (Ndc) (C021,C026,C077); Starting Contact Signal (Fr) (C021,C026); Heat Sink Overheat Warning Signal (Ohf) (C021,C026,C064) - Hitachi NES1-004SB Quick Reference Manual

Chapter 7 Explanation of Functions
7.8.13 Communication line disconnection signal (NDc)
This signal function is enabled when ModBus-RTU has been selected for the RS485 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 (C077).
External control equipment
Monitoring timer
Communication line
disconnection signal (NDc)
Item
Terminal function
Alarm relay terminal function
Communication trip time
7.8.14 Starting contact signal (FR)
The inverter outputs the starting contact (FR) signal while it is receiving an operation command.
The FR signal is output, regardless of the setting of the run command source setting (A002).
If the forward operation (FW) and reverse operation (RV) commands are input at the same time, the
inverter stops the motor operation.
Item
Terminal function
Alarm relay terminal function
Forward operation command
Reverse operation command
Starting contact signal (FR)
7.8.15 Heat sink overheat warning signal (OHF) [C064]
The inverter monitors the temperature of its internal heat sink, and outputs the heat sink overheat warning
(OHF) signal when the temperature exceeds the heat sink overheat warning level (C064).
Item
Terminal function
Alarm relay terminal function
Heat sink overheat warning level
Inverter
Function code
Function code
Function code
C021
C026
C064
Communication trip time
(C077)
Data or range of data
C021
32
C026
C077 0.00 to 99.99 (s)
C021
C026
Data or range of data
42
0. to 110. (℃)
7 - 72
Description
NDc: Communication line
disconnection signal
Setting of the limit time for
reception timeout
Data Description
FR: Starting contact
41
signal
Description
OHF: Heat sink overheat warning
signal
Setting of the threshold
temperature at which to output the
heat sink overheat warning signal