GE 90-30/20/Micro manual Control Functions

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Section 9: Control Functions

This section describes the control functions, which may be used to limit program execution and alter the way the CPU executes the application program. (Refer to Chapter 2, section 1, “PLC Sweep Summary,” for information on the CPU sweep.

Function		Description	Page
CALL	Causes program execution to go to a specified subroutine block.		4-108
DOIO	Services for one sweep a specified range of inputs or outputs immediately. (All		4-109
	inputs or outputs on a module are serviced if any reference locations on that
	module are included in the DO I/O function. Partial I/O module updates are not
	performed.) Optionally, a copy of the scanned I/O can be placed in internal
	memory, rather than the real input points.
SER	Sequential Event Recorder— collects data based on an event trigger. A function		4-114
	control block contains user-supplied information about function block
	execution, channel descriptions and operation parameters.
END	Provides a temporary end of logic. The program executes from the first rung to		4-123
	the last rung or the END instruction, whichever is encountered first. This
	instruction is useful for debugging purposes, but it is not permitted in SFC
	programming (refer to the Note on page 4-114).
MCR	Programs a Master Control Relay. An MCR causes all rungs between the MCR		4-124
and	and its subsequent ENDMCR to be executed without power flow. Logicmaster
MCRN	90-30/20/Micro software supports two forms of the MCR function, a non-nested
	form (MCR) and a nested form (MCRN).
ENDMCR	Indicates that the subsequent logic is to be executed with normal power flow.		4-127
and	Logicmaster 90-30/20/Micro software supports two forms of the ENDMCR
ENDMCRN	function, a non-nested form (ENDMCR) and a nested form (ENDMCRN).
JUMP	Causes program execution to jump to a specified location (indicated by a		4-128
and	LABEL, see below) in the logic. Logicmaster 90-30/20/Micro software
JUMPN	supports two forms of the JUMP function, a non-nested form (JUMP) and a
	nested form (JUMPN).
LABEL	Specifies the target location of a JUMP instruction. Logicmaster 90-30/20/Micro		4-130
and	software supports two forms of the LABEL function, a non-nested form
LABELN	(LABEL) and a nested form (LABELN).
COMMENT	Places a comment (rung explanation) in the program. After programming the		4-131
	instruction, the text can be typed in by “zooming” into the instruction.
SVCREQ	Requests one of the following special PLC services:		4-132
	•	Change/Read Task State and Number of Words to Checksum.
	•	Change/Read Time-of-Day Clock.
	•	Shut Down the PLC.
	•	Clear Fault Tables.
	•	Read Last-Logged Fault Table Entry.
	•	Read Elapsed Time Clock.
	•	Read I/O Override Status.
	•	Read Master Checksum
	•	Interrogate I/O
	•	Read Elapsed Power Down Time
PID	Provides two PID (proportional/integral/derivative) closed-loop control		4-165
	algorithms:
	•	Standard ISA PID algorithm (PIDISA).
	•	Independent term algorithm (PIDIND).

GFK-0467K Chapter 4 Series 90-30/20/Micro Instructions Set 4-107