EM-176A is a bidirectional speed controller for brushed DC motors. Its PWM-controlled H-bridge power stage provides efficient motor control together with forward and reverse operation, dynamic braking and freewheel functions.
The controller can be powered from a regulated or unregulated DC supply. Motor speed can be commanded using an external potentiometer or a direct analog voltage signal.
Adjustable RxI load compensation helps reduce motor-speed variation caused by changes in mechanical load. Adjustable acceleration and deceleration ramps provide smooth operation and help reduce current peaks during starting, stopping and direction changes.
The motor-speed command can be provided using an external potentiometer or a direct analog voltage signal. The standard command ranges are 0–5 V and 0–10 V.
The scale-adjustment trimmer allows the command range to be matched more closely to the required motor-voltage or speed range.
An optional auxiliary card enables bipolar analog control using a ±5 V or ±10 V voltage signal. The option also allows a centre-position potentiometer to control both motor direction and speed.
With bipolar control, one signal polarity commands forward operation and the opposite polarity commands reverse operation. The motor stops when the command is at the centre or zero position.
The controller provides a regulated +5 V auxiliary output for an external speed potentiometer. The output can supply a maximum current of 10 mA.
An optional −5 V auxiliary output is available when bipolar potentiometer control is required.
Motor-voltage regulation compensates for variations in the supply voltage, helping to maintain a stable commanded motor-voltage level.
Adjustable RxI compensation increases the motor voltage as motor current rises. This compensates for part of the voltage drop caused by motor winding resistance and helps reduce speed loss when mechanical load increases.
The adjustable ramp function controls how rapidly the motor voltage changes during starting, stopping and direction changes.
Ramp times between immediate response and three seconds can be selected. This provides smoother mechanical operation and helps prevent excessive current peaks.
The adjustable current limit restricts motor torque and protects the motor, controller and mechanical system if the motor stalls or the mechanism becomes jammed.
The current limit can be adjusted internally from 0 A to 15 A or controlled externally using a 0–5 V signal, where the full input range corresponds to a current-limit range of 0–15 A.
The reverse input changes the motor's rotational direction. Direction changes follow the selected ramp time, providing controlled deceleration and acceleration instead of an immediate reversal.
The brake input short-circuits the motor terminals through the power stage. The motor then produces a strong dynamic-braking torque that brings it to a rapid stop.
The brake command bypasses the normal ramp function and therefore acts immediately when activated.
The freewheel input disconnects the active power stage from the motor, allowing the motor to rotate freely without electrical driving or braking torque from the controller.
Like the brake command, the freewheel command bypasses the normal acceleration and deceleration ramps.
The reverse, brake and freewheel inputs use positive logic. An input voltage between 4 V and 30 V is interpreted as active, while a voltage between 0 V and 1 V, or an open input, is interpreted as inactive.
The control inputs have an impedance of 10 kΩ.
The EM-176A is suitable for conveyors, feeders, pumps, fans, valve actuators, winding equipment, positioning mechanisms and other brushed DC motor applications requiring reversible speed control, active braking and adjustable torque limitation.
| Supply voltage | 12–35 VDC |
| Overvoltage protection level | 39 V |
| Idle current | approx. 30 mA |
| Continuous motor current | 10 A |
| Peak motor current | 15 A at 20% ON / 80% OFF duty cycle |
| Motor-voltage range | 0–29 V, corresponding to 0–100% command |
| Adjustable current limit | 0–15 A |
| External current-limit control | 0–5 V corresponds to 0–15 A |
| Adjustable ramp time | 0–3 s |
| Voltage loss | 1.2 V at Im = 10 A |
| PWM frequency | 25 kHz |
| Standard auxiliary voltage | +5 V, max. 10 mA |
| Optional auxiliary voltage | −5 V |
| Standard analog command range | 0–5 V or 0–10 V |
| Optional bipolar command range | ±5 V or ±10 V |
| Analog command input impedance | 100 kΩ, pins 7 and 9 |
| Digital input, on state | 4–30 V |
| Digital input, off state | 0–1 V or open circuit |
| Digital control-input impedance | 10 kΩ, pins 5, 6 and 8 |
| Recommended control potentiometer | 4.7–47 kΩ |
| Operating temperature (Ta) | −20…+70 °C |
| Dimensions | 65 × 73 × 30 mm |
| Weight | approx. 100 g |
Ordering larger quantities +100pcs.
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