EM-348C is a four-quadrant, full-bridge driver for brushed DC motors. It is designed for applications requiring bidirectional motor control, adjustable motion profiles and advanced protection functions.
The power stage uses smooth-switching technology to reduce electromagnetic emissions. Two PWM frequencies are available: 2 kHz for higher current capacity and 16 kHz for quieter motor operation.
The full-bridge power stage supports forward and reverse motoring as well as controlled braking in both directions. This enables accurate speed control, rapid deceleration and regenerative braking.
During standby, the power stage can be configured for either brake mode or freewheel mode. Brake mode electrically restrains the motor, while freewheel mode releases it to rotate without active drive.
The FW and BW inputs start the motor in the forward and reverse directions. The STOP input stops the motor, while separate Limit-FW and Limit-BW inputs can be used for direction-specific end-limit switches.
In continuous mode, the motor runs for as long as the corresponding direction command remains active. In impulse mode, a short command starts the motor and another command changes or stops the operating state.
Adjustable acceleration and deceleration ramps provide smooth starts, stops and direction changes. The adjustable current limit protects the motor and mechanism against excessive current and torque.
During startup, the maximum available current can rise to 30 A to provide additional torque for overcoming starting friction.
The start-kick function provides additional starting effort in applications with high starting friction. The automatic-reverse function can reverse the motor according to the configured operating conditions.
At 2 kHz, the power stage provides its highest continuous and peak current capability. The 16 kHz setting enables quieter operation but reduces the available output current.
The digital inputs are divided into control and limit groups. Each group can be configured independently for NPN or PNP control logic.
The fault output is normally inactive and becomes active-high if an overtemperature or, depending on the selected parameters, a current-trip condition occurs.
Applying a high signal externally to the disable input stops the motor and prevents a new start while the signal remains active. Where permitted by the wiring instructions, several drivers can be interconnected so that a fault in one unit stops the other units.
The NPN open-collector brake output can control an external magnetic brake or braking resistor. The minimum permitted resistance depends on the system voltage.
The integrated two-wire RS-485 interface supports the Modbus RTU protocol. The bus can be used to control motor speed and direction and to adjust acceleration, deceleration and current-limit settings.
Parameter setting and monitoring are also available through the bus. Detailed communication information is provided in a separate Modbus instruction guide.
| PCB and program version | PCB v1 / EM-348-C program v1.9 |
| Supply voltage | 10–35 VDC |
| Adjustable overvoltage limit | 15–40 V, subject to hardware limitations |
| Start-up voltage | 9 V |
| Shutdown voltage | 8 V |
| Continuous current at 2 kHz, 100% PWM | 15 A (Ta = 15 °C) |
| Continuous current at 2 kHz, 5–99% PWM | 10 A (Ta = 15 °C) |
| Continuous current at 16 kHz, 100% PWM | 10 A (Ta = 15 °C) |
| Continuous current at 16 kHz, 5–99% PWM | 5 A (Ta = 15 °C) |
| Peak current at 2 kHz | 30 A for 5 s |
| Peak current at 16 kHz | 25 A for 5 s |
| Adjustable current limit | 0.1–25 A (max. 30 A at startup) |
| 6 A version current ratings | Typically approximately 2.5 times lower than the standard version |
| Overtemperature limit | 100 °C |
| Adjustable start and stop ramps | 0–5 s |
| PWM frequency | 2 kHz / 16 kHz |
| Digital input levels | High = 4–30 V / Low = 0–1 V |
| Control input impedance | typ. 47 kΩ |
| Limit and pulse input impedance (pins 2 and 3) | typ. 10 kΩ |
| Control input response time | typ. 5 ms |
| Fault output | PNP open collector, 12–22 V / max. 50 mA |
| Brake output | NPN open collector, max. 35 V / 2 A |
| Minimum braking resistance at 12 V | 6.8 Ω |
| Minimum braking resistance at 24 V | 15 Ω |
| Disable input activation | Uin > 4 V (PNP) |
| RS-485 | Two-wire half-duplex, Modbus RTU, 9600 bit/s |
| Motor and supply connectors | Max. 2.5 mm² cable |
| Control connectors | Max. 1 mm² cable |
| Dimensions | 42 × 72 × 25 mm |
| 6 A version dimensions | 42 × 72 × 18 mm |
| Dimensions with DIN-rail base | 45 × 80 × 45 mm |
| EMC | CE tested for industrial environments |
| Operating temperature (Ta) | −40…+60 °C |
| Weight | 75 g |
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