Elmo HARSFEN0602, HARmonica software manual 149, Underflow

HARSFEN0602ElmoHARmonicaSoftwareManual PRELIMINARYDRAFT

149

Initial

conditions: PVT read pointer equals

N

Motion

segment

completed

?

Yes

Read pointer ==

Exit PVT mode: Set Stop motion,

Write pointer

Yes

using the SD deceleration

No
N >= MP[2]-1		Yes
		EMERGENCY:
		QUEUE
		UNDERFLOW
Increment		Set the read
		pointer to
read pointer
		MP[1]
No
Read the read pointer row of
the PVT table and calculate
the parameters of the next
motion segment
MP[4]>0 and
(Write pointer ==	Yes	EMERGENCY:
N+1 or		QUEUE LOW
left time < MP[4])
No
Interpolate
position
command
Go to
position
controller

Figure 27 – PVT Auto Increment Mode Flow Chart

The above flow diagram differs from the basic mode in the following:

Motion queue underflow is diagnosed by the read pointer reaching the write pointer

•Emergency objects are issued for the queue low and for the queue underflow events.