Allen-Bradley SoftLogix 5800, Руководство пользователя

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194 Rockwell Automation Publication 1789-UM002K-EN-P - January 2015
Appendix A Communicate with Devices on a DeviceNet Network
Create Alias Tags
You might want to create alias tags to better represent the elements of the input
and output array tags. An alias for an I/O point does the following:
•
Provides a descriptive name for the device that is wired to the point.
•
Represents the value of the point. When one changes, the other reflects
the change.
When you enter an alias tag into programming logic, the programming software
displays the original tag, along with the alias.
If you want to choose the 1784-PCIDS card from an online list of available
devices, such as Browse Network in RSNetWorx for DeviceNet software, choose
the 1784-PCIDS card from outside of the virtual chassis.
EXAMPLE
The following logic was initially programmed by using descriptive tag names, such as start and
motor. Later, the tags were converted to aliases for the corresponding I/O devices.
• Start is an alias for the push button at bit 1 of word 0 of the module in slot 5 of the local
chassis. When the push button is on, start is on.
•
Motor is an alias for the starter contractor at bit 0 of word 0 of the module in slot 5 of the
local chassis. When motor turns on, the starter contractor turns on
.
Motor
<Local:5:O.Data[0].0>
Motor
<Local:5:O.Data[0].0>
Start
<Local:5:I.Data[0].1>
Stop
<Local:5:I.Data[0].0>