EM-337A-SPF is a parallel synchronization controller for four brushed DC motors. It includes four H-bridge power stages and is designed for actuators equipped with pulse-feedback sensors.
The controller continuously compares the pulse-feedback information from all four actuators and adjusts their operation to maintain synchronized speed and position. If the synchronization error exceeds the configured limit, all motors are stopped.
In the SPF operating mode, an analog position command is used as the common setpoint. The controller operates as a multi-axis servo driver and positions all connected actuators according to the scaled setpoint value. Control and monitoring are also available through the RS-485 interface.
Each actuator is driven by its own H-bridge power stage and provides a separate pulse-feedback signal. The controller compares the feedback from all four channels and corrects the individual motor outputs to keep the actuators synchronized.
Synchronization control compensates for differences between motors, actuators and mechanical loads. This helps prevent twisting, binding and uneven movement in structures driven by multiple actuators.
The maximum permitted position difference between the actuators can be set with a parameter. If the synchronization error exceeds this limit, the controller stops all four motors.
Stopping all channels together helps protect the actuators and mechanical structure if one motor becomes blocked, overloaded or loses its feedback signal.
The SPF firmware uses a common analog position command. The available input ranges are 0–5 V and 0–10 V.
The setpoint range can be scaled using parameters to match the required mechanical travel. The controller positions all four actuators according to the same scaled command value.
Each actuator must provide a compatible pulse-feedback signal. The maximum pulse-input frequency is 700 Hz per feedback channel.
The pulse inputs include configurable or circuit-dependent 10 kΩ pull-up or pull-down resistors. Correct input logic and sensor wiring must be selected for the feedback-sensor type.
Adjustable acceleration and deceleration ramps provide smooth starts, stops and direction changes. The ramps reduce mechanical shock and sudden motor-current peaks.
Smooth motion control is particularly important in multi-actuator structures where abrupt movement could increase synchronization error or cause mechanical binding.
The load-compensation function helps maintain synchronized movement when the four actuators are subjected to different mechanical loads.
This is useful in lifting and positioning systems where load distribution may change during movement or where the mechanism is not perfectly symmetrical.
The current limit can be adjusted between 1 A and 25 A to protect the motors, power stages and mechanical system against excessive current and force.
During motor start-up, each channel can provide a maximum current of 25 A under the specified operating conditions.
The 2 kHz PWM setting provides the highest available continuous and short-term motor-current capacity.
The 16 kHz setting moves the switching frequency above the normal audible range and provides quieter motor operation with reduced output-current capacity.
The control inputs can be configured for either NPN or PNP logic. In NPN mode, an input is active when pulled to 0–1 V. In PNP mode, an input is active when driven to 4–30 V.
This allows the controller to be used with different switches, sensors, PLC outputs and control architectures.
A 0–5 V analog position output is available for external monitoring. The output has an impedance of 1 kΩ and can be connected to a compatible analog input.
The controller includes an NPN brake output capable of switching up to 4 A. It can be used to control compatible external electromagnetic brakes or an intermediate relay.
The two-wire half-duplex RS-485 interface supports communication speeds of 9.6 kbit/s and 19.2 kbit/s.
The interface can be used for remote control, parameter setting and operating-status monitoring when supported by the installed firmware and communication protocol.
The EM-337A-SPF is available as a bare controller card or installed in a DIN-rail mounting base. Enclosed Fibox versions are also available for protected installations.
The larger Fibox PC175/100 enclosure option can include an integrated 300 VA power supply, providing a complete multi-actuator control assembly.
The EM-337A-SPF is suitable for synchronized lifting systems, adjustable platforms, hospital and care equipment, industrial tables, large hatches, roof and cover mechanisms, and other structures driven by four parallel DC actuators.
| Nominal supply voltage | 24–48 VDC |
| Operating supply-voltage range | 20–58 VDC |
| Undervoltage shutdown | 8 V |
| Overvoltage limit | 58 V |
| Idle current | < 20 mA |
| Continuous motor current at 2 kHz | 4 × 8 A |
| Continuous motor current at 16 kHz | 4 × 4 A |
| Motor current at 25% duty cycle, 2 kHz | 4 × 10 A |
| Motor current at 25% duty cycle, 16 kHz | 4 × 5 A |
| Motor current at 10% duty cycle, 2 kHz | 4 × 15 A |
| Motor current at 10% duty cycle, 16 kHz | 4 × 8 A |
| Maximum start-up current | 4 × 25 A |
| Adjustable current limit | 1–25 A |
| Temperature limit | 90 °C |
| Power-stage overtemperature shutdown | 120 °C |
| PWM frequency | 2 kHz or 16 kHz |
| NPN input, on state | 0–1 V |
| NPN input, off state | 4–30 V or open circuit |
| PNP input, on state | 4–30 V |
| PNP input, off state | 0–1 V or open circuit |
| Control-input impedance | typ. 47 kΩ or 10 kΩ, depending on input |
| Maximum pulse-input frequency | 700 Hz per feedback channel |
| Pulse-input pull-up / pull-down | 10 kΩ |
| Fault output | NPN open collector, max. 30 V / 50 mA |
| Auxiliary voltage output | 5 V, max. 20 mA |
| Analog position output | 0–5 V, Rout = 1 kΩ |
| Analog position input | 0–5 V or 0–10 V |
| Brake output | NPN, max. 4 A |
| Communication interface | Two-wire half-duplex RS-485 |
| Communication speed | 9.6 or 19.2 kbit/s |
| Supply connectors | Max. 4 mm² cable |
| Motor connectors | Max. 2.5 mm² cable |
| Control connectors | Max. 1.5 mm² cable |
| Recommended operating temperature (Ta) | −40…+60 °C |
| EMC | EN 55022B and EN 61000-6-2 / EN 61000-4-2…-6 |
| Card dimensions | 142 × 73 × 28 mm |
| Dimensions with DIN-rail base | 145 × 127 × 50 mm |
| Fibox PC150/60 enclosure | 180 × 130 × 60 mm |
| Fibox PC175/100 enclosure | 180 × 180 × 100 mm, optional integrated 300 VA supply |
| Weight | 190 g |
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