Hitachi SJ200 Series manual 175

4–48

Using Intelligent Output Terminals

Network Detection Signal

Operations and Monitoring

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.

Option

Terminal

Function Name

Output

Description

Code

Symbol

State

08

NDc

Network Detection

ON

when the communications watchdog timer

Signal

(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

Example (requires output configuration—

see page 3–46):

Required settings:

C076, C077

Inverter output

NDc

Notes:

terminal circuit

• To disable the communications watchdog timer, set

C077=00.00 sec.

H

O

OI

L

FM

CM2

12

11

• 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 for terminals [AL0], [AL1], [AL2] (requires output configuration—

see pages 4–35 and 3–46):

Inverter logic	NDc
circuit board

		AL0	AL1		AL2
	Power
See I/O specs				Load
	supply
on page 4–6.

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.