Hitachi X200 Series instruction manual Network Detection Signal Integrated ModBus

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Network Detection Signal (Integrated ModBus)

Inverter Mounting and installation

The Network Detection Signal output indicates the general status of network communications (integrated ModBus communication). 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	State	Description
Code	Symbol
08	NDc	Network	ON	when the communication watchdog timer (period
		Disconnection		specified by C077) has timed out.
		Signal (ModBus)	OFF	when the communication watchdog timer is
				satisfied by regular communications activity
Valid for inputs:		11, AL0 – AL2		Example for terminal [11] (default output
Required settings		C076, C077		configuration shown – see page 3-54):
Notes:				Inverter output
• To disable the communications watchdog timer,				terminal circuit	NDc
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	CM2		11
the watchdog time-out period with C077.
		RY

Example for terminal [AL0], [AL1], [AL2] (requires output configuration – see page 4-35 and 3-54):

Inverter logic				NDc
circuit board
		AL0	AL1		AL2
	Power
					Load
	supply

See I/O specs 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.