Mitsubishi Electronics FX1S manual Restrictions Of Some Instructions When Used With STL

FX Series Programmable Controllers STL Programming 3

3.6Restrictions Of Some Instructions When Used With STL

Although STL can operate with most basic and applied instructions there are a few exceptions. As a general rule STL and MC-MCR programming formats should not be combined. Other instruction restrictions are listed in the table below.

		Basic Instructions
	LD, LDI, AND,
Operational State	ANI, OR,ORI,	ANB, ORB,
	NOP, OUT,	MPS,MRD,	MC, MCR
	SET, RST,	MPP
	PLS,PLF

Initial and general		STL
				✔	✔	✗
states
			SET S**
		STL
Branch-	Output		SET S**	✔	✔	✗
	processing
ing and
merging
states	Transfer	STL	STL
				✔	✗	✗
	processing		SET S**
		STL

Restrictions on using applied instructions

•Most applied instructions can be used within STL programs. Attention must be paid to the way STL isolates each non-active step. It is recommended that when applied instructions are used their operation is completed before the active STL step transfers to the next step.

Other restrictions are as follows:

-FOR - NEXT structures can not contain STL program blocks.

-Subroutines and interrupts can not contain STL program blocks.

-STL program blocks can not be written after an FEND instruction.

-FOR - NEXT instructions are allowed within an STL program with a nesting of up to 4 levels.

For more details please see the operational compatibility listed in the two tables on pages 7-12,7-13.

Using ‘jump’ operations with STL

• Although it is possible to use the program jump operations (CJ instruction) within STL program flows, this causes additional and often unnecessary program flow complications. To ensure easy maintenance and quick error finding it is recommended that users do not write jump instructions into their STL programs.

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