Emerson Epsilon EP Drive 400518-01 Manual de instalación descargar pdf (Pagina 126)

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Epsilon EP-P Drive and FM-3/4 Module Reference Manual

Prior to A1 firmware in the FM-3/4, the user had no control over the timeline. If a motion initiate command was seen within

5 milliseconds from the last time a motion profile was completed, the processor assumed that the user wanted to initiate the

motion from the exact ending point of the last profile. Because of this, the processor would adjust the current motion profile

to compensate for the lost time, therefore keeping the timeline intact. The user may or may not have been aware that this was

happening. If no motion initiate was commanded within 5 milliseconds of the last motion complete point, then the timeline

was broken and started over again on the next motion profile.

The FM-3/4 module now has program instructions to allow better control of the timeline. These instructions are the “Using

Capture” and the “Using Last” instructions. Following is a description of each of the instructions:

Using Capture

The Using Capture instruction can be inserted after any Jog Initiate, Index Initiate, Dwell for Time, and Dwell for Master Dist

instructions. By inserting the Using Capture instruction, it specifies that data captured by the position capture object is to be

used as the starting point for the motion initiate. If the motion time base is realtime, then the captured time is used as the

starting point for the motion profile. If the motion time base is synchronized, then the captured master position is used as the

starting point for the profile.

Example:

Wait For (Capture.0.CaptureTriggered)

Index.0.Initiate Using Capture.0 ‘Index0,Incrmntl,Dist=5.0revs

Using Last

When the Using Last instruction is inserted after a motion initiate instruction, the time (or master position in synch motion)

of the last command complete is used as the starting point of the motion profile. Whenever a motion profile is complete, the

time/position is automatically captured behind the scenes. The Using Last instruction simply references this “automatically”

captured time or position.

The FM-3/4 module performs motion based on a concept called the timeline. The timeline allows for accurate and repeatable

motion with respect to a single point in time. The timeline guarantees that all motion profiles occur at the right time with

respect to each other.

If Index0 takes 3 seconds to complete, and Index1 takes 5 seconds to complete, by initiating Index0 and then Index 1 in a

program, the user would expect these profiles to take a total of 8 seconds to complete. It is possible though, that because of

processor timing, Index.1 does not start at exactly the same time Index0 is complete. Therefore, the two profiles could take

slightly more than 8 seconds to complete. Although the amount of time lost is extremely small (less than 5 milliseconds),

over a long period of time, this lost time can accumulate.

Keeping the timeline intact is most important in applications using synchronized motion. This is because in synchronized

motion, time is replaced by master encoder motion. If time is lost in a synchronized motion application, then master distance

is lost, and the follower position is off with respect to the master.

Prior to A7 firmware in the FM-3/4 module the user had no control over the timeline. If a motion initiate command was seen

within 5 milliseconds from the last time a motion profile was completed, the processor assumed that the user wanted to initiate

the motion from the exact ending point of the last profile. Because of this, the processor would adjust the current motion

profile to compensate for the lost time, therefore keeping the timeline intact. The user may or may not have been aware that

this was happening. If no motion initiate was commanded within 5 milliseconds of the last motion complete point, then the

timeline was broken and started over again on the next motion profile.

Example:

Index.0.Initiate ‘Index0,Incrmntl,Dist=1.5revs

Dwell For Time 1.000 Using Last

Index.1.Initiate Using Last ‘Index1,Incrmntl,Dist=3.5revs

On Profile

The On Profile instruction can be inserted after any motion type Initiate, Dwell for Time, or Dwell for Master Dist

instructions. By inserting the On Profile modifier, it specifies which Profile the instruction will run on (See Multiple Profiles

section for more information). Select from Profile 0 or Profile 1. Both Profiles sum to give a single commanded position and

commanded velocity. If no On Profile modifier is used, the motion/dwell will operate on Profile 0. All motion that is initiated

from the Assignments view operates on Profile 0.

The On Profile modifier is also used with the Jog.Stop and Gear.Stop. When stopping jog or gear motion that is operating

on Profile 1, the On Profile 1 modifier must also be used on the stop instruction.

Examples:

Index.0.Initiate 'Index 0 runs on Profile 0

Index.1.Initiate On Profile.1 'Index 1 runs on Profile 1

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