please help

[plcdp 11]

Hello, I was hoping someone might be able to point me int the right direction here as I am very much wet behind the ears in the world of PLC programming. Part of the process I'm working on has a recipricating screw that runs on a linear transducer. This range of motion seems to be fluctuating, but everything is moving too quick to visually see if there is a discrepancy betwwen cycles. I would like to add code to capture the high and low point of each cycle so I can compare. After reading through the programming manual (by the way I am using a fx3u) the only thing I came up with is the search a data stack command...but I dont fully understand how it works.... Any help or suggestions would be greatly appreciated.. Thank you, DPPLC

[Crossbow 296]

I'm confused by exactly what you're asking here. You want to log some piece of data over a cycle of the system? What kind of data? How often? For how long? Please provide a more thorough explanation of the thought process.

[panic mode 246]

i assume that you have register telling you position of the device and probably direction in which it moves. if you want to capture max position, use register and call it MAX, preset it to some low value (negative). while motion is in progress, compare if current position is greater than MAX, if so, copy value from current position register to MAX. reverse the logic for MIN position.

[plcdp 11]

Thanks for your reply to my question. OK, The data I want to capture is an analog signal coming in from a linear transducer. What I am working on is a blow molding machine. The average cycle time is 11 seconds. As the extruder comes forward and returns, the position is read by the transducer as a number so each end of the stroke can be adjusted through the HMI to determine the size of the shot. So, for example, at the start of the cycle the extruder is at 10000. When it comes forward it travels to 200. When it hits 200 the screw turns and the extruder returns to 10000, where it stops and waits for the next cycle. The actual size of the shot is what is varying. I need to determine if this is a mechanical problem (hydraulic possibly) or if the length of the shot is varying electrically as well. So, I would like to capture the numerical data coming from the actual extruder position data register, and have it "hold" the high and low number that is read during each cycle over the period of at least 10-20 cycles so I can compare them to see if that high and low point remain the same. Again I am new to this, so if I am not making any sense I appologize. Thanks for your time, plcdp

[panic mode 246]

just use what i just posted and store the values (either use innidirect addressing or simply BMOV)

[panic mode 246]

something like this

[plcdp 11]

Wow, thanks so much, I will try this tomorrow at work. plcdp

[panic mode 246]