Mitsubishi Electronics FX1S manual Rules and Techniques For STL programs

FX Series Programmable Controllers STL Programming 3

3.5Rules and Techniques For STL programs

It can be seen that there are a lot of advantages to using STL style programming but there are a few points a user must be aware of when writing the STL sub-programs.

These are highlighted in this section.

3.5.1Basic Notes On The Behavior Of STL programs

•When an STL state becomes active its program is processed until the next step is triggered. The contents of the program can contain all of the programming items and features of a standard ladder program, i.e. LoaD, AND OR, OUT, ReSeT etc., as well as applied instructions.

•When writing the sub-program of an STL state, the first vertical ‘bus bar’ after the STL instruction can be considered in a similar manner as the left hand bus bar of a standard ladder program.

Each STL step makes its own bus bar. This means that a user, cannot use an MPS instruction directly after the STL instruction (see ￿), i.e. There needs to be at least a single contact before the MPS instruction.

Note: Using out coils and even applied instructions immediately after an STL instruction is permitted.

	1
STL	X001
S005	Y000
	X000
	Y011
	X012
	Y014
	X013
	RET

•In normal programming using dual coils is not an acceptable technique. However repetition of a coil in separate STL program blocks is allowed.

This is because the user can take advantage of the STL’s unique feature of isolating all STL steps except the active STL steps.

This means in practice that there will be no conflict between dual coils. The example opposite shows M111 used twice in a single STL flow.

Caution: The same coil should NOT be programmed in steps that will be active at the same time as this will result in the same problem as other dual coils.

S30

S 31

S 32

M111

M112

M111

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