Servo vendor designs: Low-EMI systems meet medical needs

Servo drives use pulse width modulation (PWM) switching power technology made to switch current on-and-off at frequencies at or above 20 KHz. These transitions create noise signatures at much higher frequencies, typically 10’s of MHz to 1 GHz. Drives and drive systems are, therefore, required to meet stringent requirements that comply with regulations imposed by U.S. Food and Drug Administration (FDA) and Federal Communications Commission (FCC).
By Control Engineering Staff November 29, 2007

Servo drives use pulse width modulation (PWM) switching power technology made to switch current on-and-off at frequencies at or above 20 KHz. These transitions create noise signatures at much higher frequencies, typically 10’s of MHz to 1 GHz. Drives and drive systems are, therefore, required to meet stringent requirements that comply with regulations imposed by U.S. Food and Drug Administration (FDA) and

Federal Communications Commission (FCC).

Servo system vendor

Advanced Motion Controls

Medical equipment manufacturers (OEM’s) producing technology for treatment, diagnostics or closely related support services are increasingly relying on motion control for precision movements. The company says these standards are beyond those set forth by UL and CE (European Union requirements) for general industrial equipment, which mainly focus on device safety compliance.

The company says its servo drives can be built to these standards using compact PCB integrated flat wire inductors for motor outputs and power inputs, common mode filtering on logic supply input, PCB inter- and intra-layer layout techniques including grounding of separate circuitry stages and decoupling capacitors at all interface points to the drive. These implementations eliminate the need for external considerations and reduce the overall integration of the servo drives into medical equipment.

A typical example includes an independent laboratory test indicating a -10 dB level from maximum allowable across 30 MHz to 1 GHz with the servo drive operating at 80 V dc and delivering up to 10 Amps.

C.G. Masi , senior editor
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