Delta RMC151 - Manual (Page 792)

RMC70/150 and RMCTools User Manual
A virtual axis can be used as a curve master. It is sometimes desirable to gear to a virtual
axis rather than executing the curve as a function of time. All the curves using the virtual
axis as a master can be sped up or slowed down by speeding up or slowing down the
virtual axis. The virtual axis can even be moved backwards causing the curve axes to
back up. This cannot be done using the _Time master register.
When using a virtual axis as a master as described above, it is often useful to set up the
virtual axis as rotary because it will never need to be manually reset. When used as a
master, the virtual axis is typically commanded to move with a Move Velocity (37) or
Move Relative (21) command. Moving it at 1 unit/sec as the standard velocity makes
gearing ratio calculations very easy. The acceleration and deceleration provide a smooth
start and stop for the curve axis.
Cycles Status
The Cycles and Cycles (Pressure/Force) status registers hold the number of whole cycles
that have been completed. These registers are valid for the Curve Start (86), Curve Start
(Prs/Frc) (87), Sine Start (72) and Sine Start (Prs/Frc) (76) commands.
Completing a Curve
Time-Based Curves
Time-based curves will end after the specified number of cycles, and the Target
Generator Done bit will be set when the axis reaches the final point. Infinite curves
(Cycles = 0) will continue until another motion command is issued to the axis. Infinite
curves will not cause the Target Generator Done bit to turn on.
If the curve ends with a non-zero velocity or acceleration, a new motion command must
be issued within two loop times after the Target Generator Done bit has been set. If a
new command is not issued during this time, then a Closed Loop Halt will occur and the
Runtime Error bit will be set. Notice that if the Runtime Error AutoStop is set to a halt,
that halt will also occur. Use a Link Condition in a user program to check whether the
Target Generator Done bit has been set. See the Target Generator State Bits section
below.
Master-Based Curves
Master-based curves with zero-velocity endpoints will follow the curve until another
motion command is issued. When the master register is outside the range of the curve,
the curve axis will remain stopped at the appropriate endpoint. The Target Generator
Done and State Bits can be used to determine when the master has moved beyond either
endpoint. See the Target Generator State Bits section below.
Master-based curves that end with non-zero velocity endpoints will continue for two loop
times after the master moves beyond the starting or ending point. If another motion
command is not issued within two loop times of the master moving beyond the starting or
ending point, then a Closed Loop Halt will occur and the Runtime Error bit will be set.
Notice that if the Runtime Error AutoStop is set to a halt, that halt will also occur. Use a
Link Condition in a user program to check the Target Generator bits to determine whether
the master has moved beyond the endpoints. See the Target Generator State Bits
section below.
If you do not want the axis to halt after exceeding an endpoint, use the Curve Start
Advanced (88) command.
For master-based cyclic curves, the endpoints are the beginning of cycle 0, and the end
of the last cycle. Infinite cyclic curves will continue until another motion command is
issued to the axis.
Specifying a Register Address
When issuing this command from anywhere other than RMCTools, the addresses in the
Master Register command parameter must be entered as an integer value.
RMC addresses are represented in IEC format as:
%MDfile.element, where file = file number, and element = element number.
772 Delta Computer Systems, Inc.