HarmonicHarmonic Drive™ servo

of [parameter mode] to [0 r/min]. 

The deceleration time to speed command voltage is as follows: 

2-3-6 Zero clamp

In the speed mode when [speed command] is [0], the actuator may rotate slightly by force from the

driven mechanism. The [Zero clamp] function forcefully stops the actuator when the speed command is 

[0].

● Setting

[Parameter mode]→[7: zero clamp]

Take cares that the servo-lock function does not work and the 

actuator is free to rotate when:

- main and/or control power are not supplied;.

- servo-ON signal is not inputted;

- an alarm occurs

2-4 Other functions

2-4-1 Indicating of pulse counts

As shown in the figure to the right, the motion

command pulses are transmitted to the HA-655 

driver from a host. The driver drives the actuator 

corresponding to the motion command. When the 

actuator starts, the position pulses are sensed by 

the encoder and are fed back to the driver. The

HA-655 driver continues to drive the actuator until 

the error count (difference between command count 

and feedback count) comes to zero.

In the monitor mode, [command pulse], [feedback pulse], and [error pulse] can be monitored. This 

function may be effective for diagnosis.

● Indications

[Tune mode]→[3,4: error counter status], [7,8: feedback pulse], [9,A: command pulse]

2-4-2 Manual JOG operation

It is possible to operate the actuator manually for test, for tuning, and for diagnosis without commands 

from a host. Pressing the [UP] and [DOWN] keys on the front panel rotates the actuator at pre-set speed 

and at pre-set acceleration.

● Operation and setting

[Test mode]→[Jo: JOG operation], [SP: JOG speed], [Ac: JOG acceleration]

2-4-3 Monitoring inputs and operating outputs 

It is possible to monitor input ports of [clear], [servo -ON], [FWD inhibit] and [REV inhibit] for test, for 

tuning, and for diagnosis.

It is also possible to manually output signals of [in-position], [attained speed], [alarm] and so on without 

relations to the actuator state by pressing the [UP] and [DOWN] keys on the front panel outputs signals.

● Operation and setting

[Test mode]→[b：I/O monitor], [InP：Output port operation]

Chapter 3 I/O ports

Through the CN2 connector (50 pins; half pitch) the HA-655 driver communicates with a host. Details of 

the I/O ports are described in this chapter.

As the functions of the pins of the connector differ in each control mode, the functions are described 

separately by modes.

3-1 Position mode

3-1-1 I/O port layout 

3-1-3 I/O port connections in the position mode

This section describes the connection between the I/O ports and a host in the position mode

Inputs: 

The HA-655 driver provides six ports 

for inputs as shown in the figure to the 

right.

◆ Specifications

Voltage: DC24V±10%

Current: 20mA or less

 (for each port)

An input port circuit is shown in the 

figure to the right. The ports marked 

with (*) are available for absolute

encoder system only.

● Connection

The HA-655 driver does not provide 

the power supply for input signals.

Connect a [+24V] power supply for the 

signals to [CN2-1: input signal

common].

Outputs: 

The HA-655 driver provides eight ports 

for outputs as shown in the figure to 

the right.

◆ Specifications

Port: Open collector

Voltage: DC24V or less

Current: 40mA or less

 (for each port)

All ports are insulated by opto-isolators.

An output port circuit is shown in the 

figure to the right.

3-1-4 I/O port functions in the position mode

This section describes I/O port functions in the position mode.

CN2-1 Input signal common: IN-COM (input)

● Function

This is the common port for inputs: [CN2-2, -3, -4, -5, -10, -11]. Supply external power for inputs to this

the port.

● Connection

Connect [+24V] external power supply for inputs here.

CN2-2 Clear: CLEAR (input)

● Function

(1) If alarm exists:

This clears the alarm state, returns to operable state, and clears the error count to [0]. For alarms

that cannot be cleared, shut off the control power once, and turn it on again.

(2) If no alarm exists:

This clears the error count to [0]. At the same time, this clears the command count and the feedback 

count.

● Connection

Connect [NO-contact signal (a-contact)]. Refer to [CN2-1: input signal common].

CN2-3 Servo-ON: S-ON (input)

● Function

This turns the servo power for the HA-655 driver ON and OFF.

When the input is ON, the servo power of the HA-655 driver is ON and the actuator can be driven. When 

OFF, the servo power turns OFF and the motor is free to rotate.

● Connection

Connect [NO-contact signal (a-contact)]. Refer to [CN2-1: input signal common].

CN2-4 FWD inhibit: FWD-IH (input)

CN2-5 REV inhibit: REV-IH (input)

● Function

[FWD inhibit]: open state (OFF) of the input inhibits forward rotation. 

[REV inhibit]: open state (OFF) of the input inhibits reverse rotation. 

Open states (OFF) of both inputs inhibit rotation.

The inputs may be used to limit the motion range between limit sensors.