stepper motor driver-DM420A

Introduction:

DM420A  is a type  of two-phase hybrid stepping motor driver, The drive voltage of which is from 12VDC to 36VDC. It is designed for use with 2-phase hybrid stepper motor of all kinds with 20mm to 42mm outside diameter and less than 2.0A phase current. This circuit that it adopts is similar to the circuit of servo control which enables the motor run smoothly almost without noise and vibration. Hording torque when DM420A run under high speed is also significantly higher than the other two-phase driver, what’s more, the positioning accuracy is also higher. It is widely used in middle and big size numerical control devices such as curving machine, CNC machine, and computer embroider machine, packing machines and so on.

Features:

l High performance, low price

l Average current control, 2-phase sinusoidal output current drive

l Supply voltage from 12VDC to 36VDC

l Opto-isolated signal I/O

l Overvoltage, under voltage, overcorrect, phase short circuit protection

l 8 channels subdivision and automatic idle-current reduction

l 8 channels output phase current setting

l Offline command input terminal

l Motor torque is related with speed, but not related with step/revolution

l High start speed

l High hording torque under high speed

Electrical specification:

Pins assignments and description:

1) Connector Pins    Configurations

2) Pins wiring diagram:

PC’s control signals can be active in high and low electrical level. When the high electrical level is active, all control negative signals will be connected together to GND. When low electrical level is active, all control positive signals will be connected together to public port. Now give two examples(  Open collector &PNP), please check them:

Fig 1. Input port circuit (Positive connection)

PC open connector output

Fig. 2 Input port circuit ( Negtive connection)

PC PNP output

Note: When VCC=5V, R=0

When VCC=12V, R=1K, ＞1/8W

When VCC=24V, R=2K,＞1/8W

R must connect in the control signal part .

3.Function choice ( Using DIP pins to achieve this function)

1) Micro step resolution is set by SW 5,6,7,8 of the DIP switch as shown in the following table: 

2) Standstill current setting

SW4 is used for this purpose. OFF meaning that the standstill current is set to be half of the selected dynamic current and ON meaning that standstill is set to be the same as the selected dynamic current.

3) Output current setting:

The first three bits (SW 1, 2, 3)of the DIP switch are used to set the dynamic current. Select a setting

Closest to your motor’s required current

4) Semi-flow  function:

Semi-flow function is that there is not step pulse after200 ms, the driver output current automatically reduced to 40% of rated output current, which is used to prevent motor heat.

4. Pins of motor & power:

5. Mechanical Specification:

To have 20mm of space around ,cannot be placed next to other heating devices. What’s more, avoid dust, oil mist, corrosive gas, heavy humidity and high vibration. (Unit=mm)

6. Adjustment of troubleshooting

1) , the status on light’s indication
PWR: green, normal work light.
ALM: red, failure light, the motor with phase short-circuit, overvoltage and under-voltage protection.

2) Troubles

7. Driver wiring
A complete stepper motor control system should contain stepper drives, DC power supply and controller (pulse source). The following is a typical system wiring diagram