Rockwell Automation 57C610 Enhanced Basic Language, AutoMax User Manual

Page 60

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6Ć20

Task ABC

10 EVENT NAME=GAIN_OVER

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90 IF GAIN>MAX_GAIN THEN SET GAIN_OVER

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Task XYZ

30 EVENT NAME=GAIN_OVER

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105 WAIT ON GAIN_OVER

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6.6.3

OPEN CHANNEL Statement

The OPEN CHANNEL statement equates a logical name with a data

channel between two application tasks in the system. This statement

enables tasks to communicate with each other using INPUT and

PRINT statements. When a channel is opened between two tasks

and one task PRINTs to the other, the information is going to the

waiting task, not to a printer or serial port. When one task INPUTs

data from another, the data is being read from the other task that

has opened the channel.
The OPEN CHANNEL statement has two formats depending upon

which task it is being used in. The task sending data through the

channel must use the OPEN CHANNEL FOR OUTPUT format. The

task reading data from the channel must use the OPEN CHANNEL

FOR INPUT format. Multiple tasks can open the same channel for

output purposes and write data to it, but only one channel may open

the channel for input purposes and read from it.
Format for task writing to a channel:

OPEN CHANNEL FOR OUTPUT AS FILE #n, TYPE = (type)

Format for task reading from a channel:

OPEN CHANNEL FOR INPUT AS FILE #n, TYPE = (type), DEPTH = depth

n

= logical number assigned to the channel; range = 1Ć255;

the PRINT and INPUT statements must reference the same

number to identify this particular channel.

type = variable type or list of types that are to be passed through

the channel; multiple types must be separated by a

comma; this information allows the system to format each

piece of data when it passes it from one task to another.
I = single integer
D = double integer
R = real
S= string
B = boolean

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