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My company is about to build its first machines using the Allen Bradley ControlLogix processor. I am wondering what the rest of the world is using
for I/O addresses.
We currently use SLC500 and PLC5 processors on the machines that are spec'ed with Allen Bradley PLCs. On the electrical schematics, we label the I/O point and the wire to the I/O device with the PLC address for that point.
For example, a wire may have been labeled I:021/01 if it were connected to an input point in rack 2, group 1, second point. This makes sense, and I am suspect that it is similar to what the most companies are doing.
ControlLogix controllers, on the other hand, do not use this type of I/O address. You are free to refer to the I/O point with any label that you
desire. From what I understand, there is an I/O address of the form Location:Slot:Type.MemberName.SubMemberName.Bit assigned to each I/O point by the configuration process, but using this as the label may cause problems when there are more than one processor in the system (For example:
LOCAL:1:I.Data.0 can describe more than one point if you have 2 processors in two different racks in the same PLC system.
I am sure that some standard will emerge for this, if it has not already. I would appreciate any information that the list can provide.
Thanks
Randy DeMars
for I/O addresses.
We currently use SLC500 and PLC5 processors on the machines that are spec'ed with Allen Bradley PLCs. On the electrical schematics, we label the I/O point and the wire to the I/O device with the PLC address for that point.
For example, a wire may have been labeled I:021/01 if it were connected to an input point in rack 2, group 1, second point. This makes sense, and I am suspect that it is similar to what the most companies are doing.
ControlLogix controllers, on the other hand, do not use this type of I/O address. You are free to refer to the I/O point with any label that you
desire. From what I understand, there is an I/O address of the form Location:Slot:Type.MemberName.SubMemberName.Bit assigned to each I/O point by the configuration process, but using this as the label may cause problems when there are more than one processor in the system (For example:
LOCAL:1:I.Data.0 can describe more than one point if you have 2 processors in two different racks in the same PLC system.
I am sure that some standard will emerge for this, if it has not already. I would appreciate any information that the list can provide.
Thanks
Randy DeMars