Monday, August 20, 2007
Controller programming library
How to easily figure out the difference between 2 controller programming? Or more?
By point table? CVAHU02a to CVAHU01b, +FrzAlm +OaFlowSig +RaCO2 +RmRh
Following common sense, I know FrzAlm will stop fan in emergency. I don't know if those 3 additional AI are for monitoring only or acutually bring in more sequence.
By CID? +33(CO2 control) +34(outside air flow measurement and control)
Combining point table, I get a rough idea of what's the differece. But there's more.
Inputs, outputs, AV and BV assignments. I can ignore this in TXT library, since the logic layer is abstract and points are identified by their name, not the physical assignment. But in GRA library, I lose the control and the tool does not separate them. When I move programs from CVAHU01b to CVAHU02a, points are associated with their ID, not name. Very ugly! I have to manually go through each point to make sure logics are not connected to wrong points due to assignment changes.
The differences are always I/O, assignement and sequence. But the above process only applies to those controllers in the library. In real projects, things are more complicated. Normally, they don't have CID. (CID reminds me of how I differtiate controllers when I programmed them and they came from sequences.)
I have to identify them on HW drawings, in sequences. And they were checked by HW designer but this very simple result was left outside of the drawings. It's too bad that one can not pass all the useful information to downstreams.
That's why we need a revolution of the design process. Some of the key elements helping efficient engineering have to be identified and recorded at the very beginning of the job.
Great success begins at the beginning!
By point table? CVAHU02a to CVAHU01b, +FrzAlm +OaFlowSig +RaCO2 +RmRh
Following common sense, I know FrzAlm will stop fan in emergency. I don't know if those 3 additional AI are for monitoring only or acutually bring in more sequence.
By CID? +33(CO2 control) +34(outside air flow measurement and control)
Combining point table, I get a rough idea of what's the differece. But there's more.
Inputs, outputs, AV and BV assignments. I can ignore this in TXT library, since the logic layer is abstract and points are identified by their name, not the physical assignment. But in GRA library, I lose the control and the tool does not separate them. When I move programs from CVAHU01b to CVAHU02a, points are associated with their ID, not name. Very ugly! I have to manually go through each point to make sure logics are not connected to wrong points due to assignment changes.
The differences are always I/O, assignement and sequence. But the above process only applies to those controllers in the library. In real projects, things are more complicated. Normally, they don't have CID. (CID reminds me of how I differtiate controllers when I programmed them and they came from sequences.)
I have to identify them on HW drawings, in sequences. And they were checked by HW designer but this very simple result was left outside of the drawings. It's too bad that one can not pass all the useful information to downstreams.
That's why we need a revolution of the design process. Some of the key elements helping efficient engineering have to be identified and recorded at the very beginning of the job.
Great success begins at the beginning!
# posted by comfortpoint @ 4:23 PM 
