The FM 355 and FM 355-2 modules have four separate control channels. The controllers have the following features:

• Predefined controller structures for
  • Fixed setpoint control
  • Cascade controller
  • Ratio control
  • 3-component control
• Different operating modes
  • Automatic mode
  • Manual mode
  • Safety mode
  • Follow-up mode
  • Backup mode
• Sampling time (depending on the resolution of the analog inputs and the compensation input):
  • At 12 bits: 20 ms to 100 ms (FM 355‑2 only)
  • At 14 bits: 100 ms to 500 ms (depending on the number of released analog inputs)
• 2 control algorithms:
  • Self-optimizing temperature control algorithm
  • PID algorithm
• Integrated online self-optimization without configuration (FM 355‑2 only)
  • Faster adjustment to the operating point
• Convenient controller optimization
• Backup mode
  The controller can continue to control independently in the event of CPU failure or CPU stop. To this end, configurable safety setpoints or safety manipulated variables are set.
• Feed forward control
  The analog inputs can optionally be used for feed forward control in addition to actual value recording.