Electronic Keying - Allen-Bradley Compact GuardLogix 5370 User Manual

Electronic Keying

Electronic keying reduces the possibility that you use the wrong device in a
control system. It compares the device defined in your project to the installed
device. If keying fails, a fault occurs. These attributes are compared.
Attribute Description
Vendor The device manufacturer.
Device Type The general type of the product, for example, digital I/O module.
Product Code The specific type of the product. The Product Code maps to a catalog number.
Major Revision A number that represents the functional capabilities of a device.
Minor Revision A number that represents behavior changes in the device.
The following electronic keying options are available.
Keying Option Description
Compatible Lets the installed device accept the key of the device that is defined in the project when the
Module installed device can emulate the defined device. With Compatible Module, you can typically
replace a device with another device that has the following characteristics:
• Same catalog number
• Same or higher Major Revision
• Minor Revision as follows:
– If the Major Revision is the same, the Minor Revision must be the same or higher.
– If the Major Revision is higher, the Minor Revision can be any number.
Exact Match Indicates that all keying attributes must match to establish communication. If any attribute
does not match precisely, communication with the device does not occur. Exact Match is
required if you are using Firmware Manager.
Carefully consider the implications of each keying option when selecting one.
IMPORTANT Changing electronic keying parameters online interrupts connections to the device
and any devices that are connected through the device. Connections from other
controllers can also be broken.
If an I/O connection to a device is interrupted, the result can be a loss of data.
For more detailed information on electronic keying, see Electronic Keying in
Logix 5000 Control Systems Application Technique, publication
AT001.
Rockwell Automation Publication 1769-UM022C-EN-P - June 2018
Configure the Controller Chapter 4
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