Everything posted by fEsTiDiOuS
I'm working to fix/improve the functioning of a program running on an a PLC5/40E. I think high Scan Times are a big problem with this current program. ((Backstory: someone added some quasi motion control, and it sort of worked for a while. Now that it's broken, the operators of this machine want it back. )) I'll keep my question simple, PLC5's are new to me: There are 36 rungs with CPT instructions as the sole output, a third of these instruction are executed every scan. I'm going to replace them with MOV instructions. My question is, is there any sneaky PLC5 reason to do a CPT instead of a MOV? Is there a better way to do this? The CPT instructions that execute move integer values to a data file used by the HMI to control the coloration of touchscreen buttons. Thank you for your time. PS: I'm new-ish to this forum, please feel free to let me know if my question was asked correctly or not.
I suggest using GSV's sparingly, they really slow your program down. I don't know how much accuracy you need. If you make a logic clock with a timer and counters that is corrected once a day with a GSV your program will run a lot faster than if you execute a GSV every cycle.
Amanda I think they are trying to tell you is that the PLC is big-endian, and the micromotion is little-endian. It's something that is corrected/converted mostly automatically, but not here. The wikipedia article on 'endianness' is pretty good: https://en.m.wikipedia.org/wiki/Endianness Unfortunately in your specific case the problem is being made more confusing by the complicated way in which REAL numbers (that is numbers with a decimal point) are stored. I'm new at this. Are ControllLogix PLC's big-endian? Eddie your answer is amazing. I couldn't use your link though. Here is a shortened link to the same place: https://goo.gl/Jmt9D2 I found this piece that very nicely explains IEEE 754: http://www.oxfordmathcenter.com/drupal7/node/43