Example: Calculated tags for monitoring production lines

Creating a state machine tag for OEE

In order to explain how to create a state machine tag for OEE measuring, we will use the following example.

We have a production line with 5 different units in a lane. We call these units U1, U2, U3, U4 and U5.

We want to be able to generate a state machine tag that tells us the current state of the production line.

There are multiple ways to do this, and we will include some of them in this example.

In the first few cases we only use:

S: Unit is stopped

The notation for the tag Stopped on unit 1 is then U1S.

Later on, we use:

S: Stopped

NF: Unit receives no feed from previous unit in the production line

B: Unit is blocked from sending product to the next unit in the production line

 

Case 1: Only one machine can stop at a time

U1S+U2S*2+U3S*3+U4S*4+ U5S*5

Will return: The machine that caused stop (1,2,3,4, or 5) or otherwise return 0. 

 

Case 2: Several units can stop 

U1S+U2S*2+U3S*4+U4S*8+ U5S*16

Will return: The machine or machines that caused stop with a uniquely identifiable number or otherwise return 0.