Hitachi SJ700-2 instruction manual DC braking DB setting

Chapter 4 Explanation of Functions

4.2.19 DC braking (DB) setting

The DC braking function allows you to apply DC braking to the motor according to the load on the motor.

You can control DC braking in two ways: the external control through signal input to intelligent input terminals and the internal control to be performed automatically when the motor is started and stopped.

Note that the motor cannot be stopped by DC braking if the load on the motor produces a large moment of inertia.

Related code

A051: DC braking enable

A052: DC braking frequency setting

A053: DC braking wait time

A054: DC braking force during deceleration

A055: DC braking time for deceleration

A056: DC braking/edge or level detection for [DB] input

A057: DC braking force for starting

A058: DC braking time for starting

A059: DC braking carrier frequency setting

C001 to C008: Terminal [1] to [8] functions

Item	Function code	Data or range of data	Description
		00	Internal DC braking is disabled.
DC braking enable	A051	01	Internal DC braking is enabled.
		02	Internal DC braking is enabled. (The braking
			operates only with the set braking frequency.)
DC braking			With internal DC braking enabled, DC braking is
	A052	0.00 to 60.00 (Hz)	started when the output frequency reaches the
frequency setting
			set braking frequency.
DC braking wait			The DC braking wait time specifies the delay in
	A053	0.0 to 5.0 (s)	starting DC braking after the set braking time has
time
			elapsed or the DB terminal has been turned on.
DC braking force
during deceleration/	A054/A057	0. to 100. (%)	"0" specifies the smallest force (zero current);
DC braking force for			"100" specifies the largest force (rated current).
starting
DC braking time for	A055	0.0 to 60.0 (s)	This setting is valid for the external DC braking in
deceleration			edge mode or for the internal DC braking.
DC braking/edge or	A056	00	Edge mode (See examples 1-a to 6-a.)
level detection for		01	Level mode (See examples 1-b to 6-b.)
[DB] input
DC braking time for			This setting is valid for the internal DC braking.
	A058	0.0 to 60.0 (s)	DC braking is started when the motor-start
starting
			command is input.
DC braking carrier	A059	0.5 to 15 (kHz)	Unit: kHz
frequency setting

(1) Carrier frequency for DC braking

Use the DC braking carrier frequency setting (A059) to specify the carrier frequency for DC braking. Note that setting the carrier frequency above 5 kHz automatically lowers the braking force.

See the following graph showing the operation of the DC braking force limiter:

100

90

80

(75)

	70
Maximum braking	60
	50	(46)
force (%)
	40	(34)
	30	(22)

20						(10)
10
3	5	7	9	11	13	15

DC braking carrier frequency (kHz)

DC braking force limiter

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