GE 90-30/20/Micro manual Power Flow In and Out of a Function

2

For functions which operate on tables, a length can be selected for the function. In the following function block, a string length of up to 256 words can be selected for the logical AND function.

_____

(enable) — AND	— (ok)
???????—I1	Q—???????
???????—I2

_____

Timer, counter, BITSEQ, and ID functions require an address for the location of three words (registers) which store the current value, preset value, and a control word or “Instance” of the function.

_____

(enable) —ONDTR— Q 1.00s

(reset) —R

???????—PV

_____

(address)

Power Flow In and Out of a Function

Power flows into a function block on the upper left. Often, enabling logic is used to control power flow to a function block; otherwise, the function block executes unconditionally each CPU sweep.

Enabling logic
	Power flow into the function
		Power flow out of the function
¯	_____

%I0001 ¯				¯	%Q0001
——— ————		MUL_————————————————————————( )—
		INT			^
%R0123 —I1			Q—%R0124		Displays state
					of reference
CONST —I2
00002	_____

Note

Function blocks cannot be tied directly to the left power rail. You can use %S7, the ALW_ON (always on) bit with a normally open contact tied to the power rail to call a function every sweep.

Power flows out of the function block on the upper right. It may be passed to other program logic or to a coil (optional). Function blocks pass power when they execute successfully.

GFK-0467K Chapter 2 System Operation 2-29