Rockwell Automation 20A PowerFlex 70EC/700VC - Manual (Page 113)

Stop Modes 109
Stop Modes Several methods are available for braking or stopping a load as described in the
table below.
In addition to these modes, the drive can be programmed for “Coast” and “Ramp to
Hold,” which are described in further detail in this section.
Configuration
•
[Stop/Brk Mode A], parameter 155
•
[Stop/Brk Mode B], parameter 156
– 0 = Coast
– 1 = Ramp
– 2 = Ramp to Hold
– 3 = DC Brake
– 4 = Fast Brake (PowerFlex 70 & 700 Only)
•
[DC Brk Lvl Sel], parameter 157
– 0 = “DC Brake Lvl” – selects parameter 158 as the source for the DC brake
level
– 1 = “Analog in 1”
– 2 = “Analog in 2”
•
[DC Brake Level], parameter 158 – sets the DC brake level in amps, when
parameter 157 = “DC Brake Lvl”
•
[DC Brake Time], parameter 159 – sets the amount of time that DC braking is
applied after the ramp (if any).
•
[Flux Braking], parameter 166
– 0 = Disabled, 1 = Enabled
•
[Digital InX Sel], parameters 361-366
– 13 = “Stop Mode B” – setting a digital input to this function allows the use
of a digital input to switch between Stop Mode A (open input) and Stop
Mode B (closed input).
70EC 700VC 700H
✔ ✔
Method Use When Application Requires . . . Braking Power
Ramp
•
The fastest stopping time or fastest ramp time for speed changes
(external brake resistor or regenerative capability required for ramp
times faster than the methods below).
•
High duty cycles, frequent stops or speed changes. (The other
methods may result in excessive motor heating).
Most, if an
external resistor
or regenerative
device is
connected.
Fast
Brake
•
Additional braking capability without use of an external brake resistor
or regenerative unit, but only effective during stop events, not speed
changes.
Important: For this feature to function properly the active Bus Reg
Mode A or B must be set to Adjust “Freq” and NOT be “Disabled”. More than Flux
Braking or DC
Brake
Flux
Braking
•
Fast speed changes and fast stopping time.
•
Typical stop from speeds below 50% of base speed (“Flux Braking”
will likely stop the load faster than “Fast Brake” in this case).
Important: This can be used in conjunction with “Ramp” or “Ramp to
Hold” for additional braking power or with “Fast Brake” or “DC Brake”
for speed changes.
Important: For this feature to function properly the active Bus Reg
Mode A or B must be set to Adjust “Freq” and NOT be “Disabled”.
More than DC
Brake
DC
Brake
•
Additional braking capability without use of external brake resistor or
regenerative units. Less than above
methods