DLB is a load variation fault usually used in hoisting type application. See below for more info.

Load variation detection:
This detection is only possible with the High-speed hoisting function. It can be used to detect if an obstacle has been reached, triggering a sudden (upward) increase or (downward) decrease in the load. Load variation detection triggers a [Dynamic load fault] (dLF). The [Dyn. load Mgt.] (dLb) parameter can be used to configure the response of the drive in the event of this detected fault. Load variation detection can also be assigned to a relay or a logic output.

There are two possible detection modes, depending on the configuration of high-speed hoisting

• Speed reference mode
  • [High speed hoisting] (HSO) page 205 is set to [Speed ref] (SSO).
  • Torque variation detection.
    • During high-speed operation, the load is compared to that measured during the speed step. The permissible load variation and its duration can be configured. If exceeded, the drive switches to fault mode.
• Current limitation mode
  • [High speed hoisting] (HSO) page 205 is set to [Current Limit] (CSO).
    • On ascend, during high-speed operation, an increase in load will result in a drop in speed. Even if high-speed operation has been activated, if the motor frequency drops below the [I Limit Frequency] (SCL) threshold page 205, the drive will switch to fault mode. The detection is realized only for a positive variation of the load and only in the high speed area (area upper to [I Limit Frequency] (SCL)).
    • On descend, operation takes the form of Speed reference mode.

Released for:Schneider Electric New Zealand