GE 90-30/20/Micro manual Enhanced do I/O Function for 331 and Later CPUs

4

Enhanced DO I/O Function for 331 and Later CPUs

Caution

If the Enhanced DO I/O function is used in a program, the program should not be loaded by a version of Logicmaster 90-30/20 software prior to 4.01.

An enhanced version of the DO I/O (DOIO) function is available for Release 4.20, or later, of Models 331 and later CPUs. This enhanced version of the DOIO function can only be used on a single discrete input or discrete output 8-point, 16-point, or 32-point module.

The ALT parameter identifies the slot in the main rack that the module is located in. For example, a constant value of 2 in this parameter indicates to the CPU that it is to execute the enhanced version of the DOIO function block for the module in slot 2.

Note

The only checking done by the enhanced DOIO function block is to check the state of the module in the slot specified to see if the module is okay.

The enhanced DOIO function only applies to modules located in the main rack. Therefore, the ALT parameter must be between 2 and 5 for a 5-slot rack or 2 and 10 for a 10-slot rack.

The start and end references must be either %I or %Q. These references specify the first and last reference the module is configured for. For example, if a 16-point input module is configured at %I0001 through %I0016 in slot 10 of a 10-slot main rack, the ST parameter must be %I0001, the END parameter must be %I0016, and the ALT parameter must be 10, as shown below:

	_____
%I0001		%Q0001
—— ———DO_IO———————————————————————————————————————————————————————————( )-
%I0001 -ST
%I0016 -END
	IO —ALT
	_____

The following table compares the execution times of a normal DOIO function block for an 8-point, 16-point, or 32-point discrete input/output module with those of an enhanced DOIO function block.

	Normal DOIO	Enhanced DOIO
Module	Execution Time	Execution Time
8-Pt Discrete Input Module	224 microseconds	67 microseconds
8-Pt Discrete Output Module	208 microseconds	48 microseconds
16-Pt Discrete Input Module	224 microseconds	68 microseconds
16-Pt Discrete Output Module	211 microseconds	47 microseconds
32-Pt Discrete Input Module	247 microseconds	91 microseconds
32-Pt Discrete Output Module	226 microseconds	50 microseconds

GFK-0467K Chapter 4 Series 90-30/20/Micro Instructions Set 4-113