Rockwell Automation 20A PowerFlex 70EC/700VC - Manual (Page 30)

26 DC Bus Voltage / Memory
Even if non-consecutive Datalinks are used (in the next example, Datalinks A1 and
B2 would not be used), data is still returned in the same way.
32-bit data is stored in binary as follows:
Example
Parameter 242 - [Power Up Marker] = 88.4541 hours
MSW = 13
decimal = 1101 binary = 2 16 + 2 18 + 2 19 = 851968
LSW = 32573
851968 + 32573 = 884541
DC Bus Voltage /
Memory [DC Bus Voltage] is a measurement of the instantaneous value. [DC Bus Memory]
is a heavily filtered value or “average” bus voltage. Just after the pre-charge relay is
closed during initial power-up, bus memory is set equal to bus voltage. Thereafter it
is updated by ramping at a very slow rate toward the instantaneous bus voltage [DC
Bus Voltage]. The filtered value ramps at approximately 2.4V DC per minute (for a
480V AC drive).
Bus memory is used as a comparison value to sense a power loss condition. If the
drive enters a power loss state, the bus memory will also be used for recovery (e.g.
pre-charge control or inertia ride through upon return of the power source) upon
return of the power source. Update of the bus memory is blocked during
deceleration to prevent a false high value caused by a regenerative condition.
Digital Inputs Digital Input Configuration
Inputs are configured for the required function by setting a [Digital Inx Sel]
parameter (one for each input). These parameters cannot be changed while the drive
is running.
Input Function Detailed Descriptions
•
Stop-Clear Faults
An open input will cause the drive to stop and become “not ready”. A closed
input will allow the drive to run when given a Start or Run command.
If “Start” is configured, then “Stop - Clear Faults” must also be configured.
Otherwise, a digital input configuration alarm will occur. “Stop - Clear Faults”
is an optional setting in all other cases.
An open to closed transition is interpreted as a Clear Faults request. The drive
will clear any existing faults.
If the “Clear Faults” input function is configured at the same time as “Stop -
Clear Faults”, then it will not be possible to reset faults with the “Stop - Clear
Faults” input.
Datalink Most/Least Significant Word Parameter Data (decimal)
A1 -Not Used- 0 0
A2 MSW 242 13
Datalink Most/Least Significant Word Parameter Data (decimal)
A2 MSW 242 13
B1 LSW 242 32573
MSW 2 31 through 2 16
LSW 2 15 through 2 0
70EC 700VC 700H
✔ ✔
70EC 700VC 700H
✔ ✔