We check for obscure but significant errors in Advanced PID blocks that have caused problems for clients. You will want to check these blocks, which might have issues.
An improved version of Function Code 156 introduced New Algorithm types:
Spec S18 accepts new algorithm types 10, 11, 12, and 13, which functionally replace old types 0, 1, 2, and 3, respectively (i.e., S18=1x executes the new replacement algorithms, S18=0x executes the original algorithms). The original algorithms were kept intact to keep backward compatibility with existing configurations that may rely on the original behavior.
The new replacement APID algorithms correct the following problems (these problems continue to exist in the original algorithms):
Increase/Decrease Inhibit: When the increase or decrease inhibit is active (Specification S9 = 1, and/or S10 = 1), a rapid, unexpected change in output may occur depending on changing error signal, changing output high and/or low limits (Specification S16 and S17), and the tuning parameters.
Advanced PID Module 1,11,03 Block 1870 using old algorithm with inhibit inputs.
The documentation for the Function Code 156 Advanced PID block says:
Note: Do not use the output block increase (or decrease) flag if using the quick saturation recovery option (S19 equals zero).
We flag this with a message as well.
Advanced PID Module 1,21,03 Block 2306 using block increase flag with S19=0
Advanced PID Module 1,21,03 Block 2307 using block decrease flag with S19=0
This set of messages alerts you to places where the FC 156 Advanced PID block is misused, based on ABB service bulletins listed in our file.
In this example, the Block Increase/Decrease Flag Outputs are in use. The documentation indicates that you should not use the output block increase or decrease flag if the quick saturation recovery option (S19 = 0) is being used.
Advanced PID Module 4,50,02 Block 2380 using block increase flag with S19=0.
Both Block Increase BI and Block decrease BD outputs are in use, which is contrary to the documentation. S19 = 0, indicating the quick recovery form of the algorithm is being used.
It is possible to change the specifications to eliminate these messages. This should be done in close coordination with a DCS specialist. The important point about the error message is that you can look for hints that problems with outputs and reset are cause by the specs rather than by the inputs.
This error can be built directly into Hyperview. For more information, see the article Building error reports into the M14.