Danfoss VLT Series Programming Manual page 176

Programming
Continuous motion
The axis is processing an endlessly ongoing motion
command. The axis only leaves this state, when the
currently ongoing (continuous) motion is aborted by
another (non-continuous) motion command.
6.5.2 General Input/Output Behavior
6.5.2.1 Function Blocks with Execute Input
The parameters are used with the rising edge of the
Execute input. To modify any parameter, change the input
parameter(s) and trigger the Execute input again. Do not
change references or in/out variables while Busy is TRUE. If
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the functionality needs an abort first (for example, internal
closing of a file or abort of an SDO transfer), the abort is
processed first and the functionality with the new
parameters is started afterwards. This also includes checks
for validity of the inputs (for example, when retriggering
with invalid inputs, the abort is done first and afterwards
an error is signaled at the function block).
Retrigger the Execute input to use the explicit Abort input
(see chapter 6.5.4.24 DD_Trace_ISD51x).
Output exclusivity
The outputs Busy, Done, Error, and CommandAborted are
mutually exclusive: only 1 of them can be TRUE on 1
instance of a function block at the same time. If Execute is
TRUE, 1 of these outputs must be TRUE. Only 1 of the
outputs Active, Error, Done, and CommandAborted is set at
the same time.
The outputs Done, Error, ErrorInfo, and CommandAborted
are reset with the falling edge of Execute. However, the
falling edge of Execute does not stop or even influence the
execution of the actual function block. Even if Execute was
reset before the function block completed, 1 of the
outputs Done, Error, or CommandAborted is set for exactly
1 cycle. If an instance of a function block receives a new
rising edge at the Execute input before it finished (as a
series of commands on the same instance), the function
block will not return any feedback, such as Done or
CommandAborted for the previous action.
Done
The Done output is set when the commanded action has
been completed successfully (see case 3 in Illustration 6.19.
If an error occurs during the execution of the functionality,
the Error output is set, while the other outputs are FALSE
(see case 2 in Illustration 6.19).
With multiple function blocks working at the same axis in
a sequence, the following applies: When 1 movement of an
axis is interrupted with another movement on the same
axis without having reached the final goal, Inxxx of the 1
function block is not set, but CommandAborted is set (see
case 1 in Illustration 6.19).
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VLT Integrated Servo Drive ISD
CommandAborted
Illustration 6.19 Behavior of the Execute/Done Style Function
Blocks
Busy
The output Busy reflects that the function block is not
finished and new output values can be expected. Busy is
set at the rising edge of Execute and reset when 1 of the
outputs Done, CommandAborted, or Error is set. The
function block must be kept in the active loop of the
application program for at least as long as Busy is TRUE,
because the outputs may still change.
Inxxx
The outputs InVelocity, InGear, InTorque, and InSync (from
now on referred to as Inxxx) behave differently to the
Done output.
If the function block is active, Inxxx is TRUE when the set
or actual value (refer to DD_ValueSourceSettings_ISD51x for
this selection) equals the commanded value. It is FALSE
when, later, they are unequal. For example, the InVelocity
output is TRUE when the set or actual velocity (see
DD_ValueSourceSettings_ISD51x) is equal to the
commanded velocity. This is similar for InGear, InTorque,
and InSync outputs in the applicable function blocks.
With multiple function blocks working on the same axis in
a sequence, the following applies: When 1 movement of an
axis is interrupted with another movement on the same
axis without having reached the final goal, Done of the 1
function block is not set, but CommandAborted is set (see
case 1 in Illustration 6.20).
If an error occurs during the execution of the functionality,
the Error output is set, while the other outputs are FALSE
(see case 2 in Illustration 6.20).
st
Inxxx is updated even if Execute is FALSE if the function
block has control of the axis (Active and Busy are TRUE (see
case 3 in Illustration 6.20).
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510 System
Execute
Busy
Active
Done
Error
Case1 Case2 Case3
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