Hitachi L2002 - Manual (Page 193)

L200
2
Inverter
Oper
ations
and Monitor
ing
4–49
Network Detection Signal
The Network Detection Signal output indicates the general status of network communi-
cations. The inverter has a programmable watchdog timer to monitor network activity.
Parameter C077 sets the time-out period. If communications stop or pause longer than
the specified time-out period, the Ndc output turns ON.
Additionally, the inverter can respond to a communications time-out in various ways.
Refer to the following diagram (top of next page). You configure the desired response
via function C076, Communications Error Select. This selects whether or not you want
the inverter to trip (alarm with error code E60) and whether to stop the motor or just let it
coast. Together, parameters C076 and C077 set the network detection watchdog time-out
and the inverter’s response.
Option
Code
Terminal
Symbol
Function Name
Output
State
Description
08 NDc Network Detection
Signal ON when the communications watchdog timer
(period specified by C077) has timed out
OFF when the communications watchdog timer is
satisfied by regular communications activity
Valid for outputs: 11, 12, AL0 – AL2
Required settings: C076, C077
Notes:
•
To disable the communications watchdog timer, set
C077=00.00 sec.
• If you set Communications Error Select to
“Disable” (C076=02), you still have the option of
using the Network Detection Signal and setting the
watchdog time-out period with C077.
RY
+
–
Example (requires output configuration—
see page
3–54 ):
Inverter output
terminal circuit NDc
12 11 CM2
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 .
NDc
Load
Power
supply