When selecting stepper motors and stepper drivers, we generally recommend that each stepper driver be paired with only one stepper motor. However, in practical applications, multiple motors may need to operate synchronously, leading some users to consider using a single driver to drive multiple stepper motors. We do not recommend this approach.
In theory, a single driver can drive multiple stepper motors. Depending on the application method, this can be divided into two scenarios: time-sharing operation and synchronous operation.
Time-Sharing Operation:
Multiple stepper motors share a single stepper driver, operating in a time-sharing manner. The current and power ratings of the stepper driver and power supply can be selected based on the requirements of a single stepper motor. The respective movements of the two stepper motors are switched via relays. In this configuration, the driver only drives one motor at a time, switching between motors through the relay.
However, this approach has two main drawbacks:
- Loss of accuracy: During relay switching, the motor loses excitation, which may cause the rotor to shift position. Repeated switching can result in cumulative positioning errors. Additionally, after switching, the motor re-enters the energized state and may have lost its reference position within the system. If a closed-loop driver is used, this may even trigger a fault alarm (e.g., overcurrent or position error).
- Risk of damage: If the relay fails or the control program contains errors, the load may exceed the driver's maximum rated power, potentially damaging both the stepper motor driver and the power supply.
Synchronous Operation:
When multiple stepper motors operate synchronously while sharing a single driver, the maximum output current of the stepper motor driver must be greater than or equal to the sum of the rated currents of all connected stepper motors. Additionally, because the back-EMF (back electromotive force) generated during synchronous start and stop of the stepper motors is significantly higher, it places additional stress on the driver, which can shorten its service life in this operating condition.
In summary, to ensure optimal motor performance and protect the driver, we do not recommend using a single driver for multiple stepper motors.
If your application requires multiple motors to operate synchronously, consider the following solutions:
- Configure multiple drivers with identical parameters, and then send the same pulse, direction, and enable signals to each driver from the controller, so that all motors run identically and simultaneously.
- If you only need two motors to operate synchronously, consider using our DMAI series stepper drivers: DM456AI and DM480AI. These drivers are specifically designed to synchronize two motors, allowing both motors to follow identical motion profiles.