GE 90-30/20/Micro manual Contents

Contents

Chapter 1	Introduction	1-1
	Additional Reference Information: See the appendices in the back of this manual....	1-2
Chapter 2	System Operation	2-1
	Section 1: PLC Sweep Summary	2-2
	Standard Program Sweep	2-2
	Sweep Time Calculation	2-6
	Housekeeping	2-6
	Input Scan	2-7
	Application Program Logic Scan or Solution	2-8
	Output Scan	2-9
	Logic Program Checksum Calculation	2-9
	Programmer Communications Window	2-9
	System Communications Window (Models 331 and Higher)	2-10
	PCM Communications with the PLC (Models 331 and Higher)	2-12
	Standard Program Sweep Variations	2-13
	Constant Sweep Time Mode	2-13
	PLC Sweep When in STOP Mode	2-13
	Communication Window Modes	2-14
	Key Switch on 350 and 360 Series CPUs: Change Mode and Flash Protect	2-14
	Using the Release 7 and Later Key Switch	2-14
	Clearing the Fault Table with the Key Switch	2-14
	Enhanced Memory Protect with Release 8 and Later CPUs	2-15
	Section 2: Program Organization and User References/Data	2-16
	Subroutine Blocks (Series 90-30 PLC only)	2-16
	Examples of Using Subroutine Blocks	2-18
	How Blocks Are Called	2-19
	Periodic Subroutines	2-19
	User References	2-20
	Transitions and Overrides	2-21
	Retentiveness of Data	2-21
	Data Types	2-23
	System Status References	2-24
	Function Block Structure	2-26
	Format of Ladder Logic Relays	2-26
	Format of Program Function Blocks	2-27
	Function Block Parameters	2-28
	Power Flow In and Out of a Function	2-29
	Section 3: Power-Up and Power-Down Sequences	2-30
	Power-Up	2-30
	Power-Down	2-33
	Section 4: Clocks and Timers	2-34

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