This is part of 2.1.0 – latest release.

MLxRestart

0.1.0

system

Resume buffered motions. Used to resume motion after MLxHold.

Check the state transitions diagram to see the role of this function.

💡 Check the sample implementation in the code examples .

Version history

0.1.0

05 Jan 2021 deGroot

Changes

Changed:

source code ported
version number reset
now using semantic versioning

Prerequisites

prerequisite	state
Key switch	`REMOTE`

Overview

kind	name	type	comment
input	Enable	`BOOL`	Enable this Function Block.
output	Sts_EN	`BOOL`	Enable bit. This bit will stay high as long as the instruction is enabled.
output	Sts_DN	`BOOL`	Done bit. This bit will turn high when the instruction has finished.
output	Sts_ER	`BOOL`	Error bit. Indicates an error during instruction execution. Call MLxGetErrorDetail for more information.
in_out	MLX	`MLxData`	The MLxData Controller Scope tag.

Details

Enable

BOOL

For starting this function block. On a rising edge of this input the internal processing will start which is indicated by the Sts_EN status signal.

Internal processing steps typically involve:

checking if required conditions are met
sending the command data to the robot controller (immediately)

Since the status bits will only be updated as long as the Enable is active, it is necessary to keep the input enabled until the FB has completed its entire lifecycle which is signalled by the Sts_DN (done) status signal.

Disabling the input too early can mess up the MotoLogix command interface and lead to a hangup situation.

Sts_EN

BOOL

Status Enabled signal which tells that the FB is currently enabled. It reflects the status of the Enable input.

A common use for Sts_EN is in combination with the Sts_DN (or Sts_PC) signal. This filters the old status which is important because in the PLC scan where the FB gets enabled the Sts_DN still has the status from its previous run (which is probably high) until the FB call is processed.

CASE state OF
...
10:
  // enabling the FB
  someMLxFB.Enable := TRUE;

  // condition to proceed after FB finished
  // --> Sts_DN still has its old status from previous run
  IF (someMLxFB.Sts_DN AND someMLxFB.Sts_EN) THEN
    state := state + 10;
  END_IF;

20:
  ...
END_CASE;

// FB call
someMLxFB(...);
// --> now Sts_DN has the new status

Sts_DN

BOOL

Status done signal which tells that the FB has finished. This means the Enable input can now safely be disabled as the FB has completed its lifecycle.

This status signal keeps its status until the next time this FB is enabled. See Sts_EN on how to filter any old status.

Sts_ER

BOOL

Status error signal which tells that the FB has failed. The Enable input can now be disabled as the FB has aborted its lifecycle.

Now it is important to find the cause of the error. In most cases the robot controller has generated an alarm which explains what the problem is.

Recommended next steps:

Read the alarm details using MLxGetErrorDetail
Fix the issue described in the alarm details (e.g. parameter out of range)
Reset the alarm using MLxReset (also clears the motion queue) or MLxResetAndHold (resets the alarm but leaves the motion queue in place).
Restart the application

If Sts_ER becomes active but the robot controller does not generate an alarm you should check the SystemState and the conditions/prerequisites for using the FB.

This status signal keeps its status until the next time this FB is enabled. See Sts_EN on how to filter any old status.

MLX

MLxData

The MotoLogix variable which acts as the shared memory for a MotoLogix system.

As the PLC runs through its scan cycle each active MotoLogix FB will read from- and write to this MotoLogix variable.

It is also used for processing the data red from- and sent to the robot controller.

There are a few important rules:

MLxCommunicationRead must be called at the very beginning of the PLC scan cycle.
MLxCommunicationWrite must be called at the very end of the PLC scan cycle.
All other MotoLogix FB’s used in your application must be called inbetween.
All off this must be handled by the same PLC task, respecting above rules.

Failing to follow above rules can lead to inconsistent data being sent to the robot controller which could result in unexpected motion.

Implementation

Snippet of the function call:

fbRestart : ARRAY[0..0] OF MLxRestart;

// fbRestart[0].Enable := ;
fbRestart[0]( MLX := dummy );
//  := fbRestart[0].Sts_EN;
//  := fbRestart[0].Sts_DN;
//  := fbRestart[0].Sts_ER;