Motor driver and servo drive system

A motor driver configured to supply electrical power to a motor on a basis of a control command sent periodically at a rate according to a network communication period of the communication network and sent from a higher-level controller connected to the motor driver via the communication network, the motor driver comprising:

• a network frame receiver configured to receive the control command via the communication network at the periodical rate;
• a user program processor configured to perform program processing of a user program created by a user;
• a servo controller configured to output a servo control command, the servo control command being based on the control command;
• and
• a drive controller configured to supply electrical power to the motor, the electrical power being based on the servo control command, wherein
• when the user program processor performs the program processing:
• the user program processor is configured to start the user program according to each of activation signals generated at respective receptions of the control command to cause the user program to perform the program processing on the control command to convert the control command into a command corresponding to the user program, in synchronization with the network communication period of the control command when the network frame receiver receives the control command;
• and
• the servo controller is configured to output the servo control command, the servo control command being based on the control command resulting from the program processing.