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Brand advantage: Allen Bradley, BentlyNevada, ABB, Emerson Ovation, Honeywell DCS, Rockwell ICS Triplex, FOXBORO, Schneider PLC, GE Fanuc, Motorola, HIMA, TRICONEX, Prosoft etc. Various kinds of imported industrial parts

B&R 7DO135.70 Digital output module

On the basis of the computed minimum permissible mains voltage, the tripping threshold for the mains undervoltage detection function can be varied within appropriate limits using parameter Net Underv Trip (1.10). Positive parameter values increase the safety reserve to this computed minimum voltage, but reduce the tolerance distance to the line voltage, and thus permit smaller mains voltage fluctuations; negative values reduce the safety reserve, but increase the tolerance distance. The factory setting for this parameter is 0 %. This ensures dependable operation in the regenerative range. Negative values are limited to a maximum of -10 %; values beyond this cannot be set. The crucial factor behind this negative limitation is that the motor’s EMF in regenerative mode is the critical voltage, and not the armature voltage. Armature voltage and EMF are motor-specific, and may diverge from each other in this order of magnitude. Negative entries in this parameter may, however, endanger the drive’s safety, if they do not coincide with the motor’s EMF-specific data! It remains at the user’s discretion whether this parameter is to be altered.

This message indicates that

 • in regenerative mode for decelerating in the machine's rated operating point, the ratio between minas voltage and motor voltage is approaching the critical range (1...5 % before disconnection on fault). In the alarm range, however, deceleration mode is still possible and permissible. If the mains voltage continues to fall, a disconnection on fault must be anticipated, since otherwise there will be a risk of shoot-through. • in motoring mode, the ration between mains voltage and motor voltage has dropped into the alarm range, and a disconnection on fault is imminent. In the alarm range, however, the drive's function is still assured. Any further drop in the mains voltage will trigger a disconnection on fault In parameter Net Fail Time (1.11) the maximum tolerated mains voltage failure time is set. In case of mains undervoltage the drive is blocked and alarm A02 is displayed during this time. If during this time the mains voltage returns to a voltage level higher than the trigger level the drive restarts automatically. After this time elapsed and the mains voltage did not return to a voltage level higher than the trigger level the drive stops operation and fault F09 is displayed. Auto Reclosing is not possible in this case. Auto Reclosing is prevented if Net Fail Time = 0,0sec is set. In this case the drive will always stop operation with fault message F09 displayed if mains undervoltage occurs