Mr JJ

Thanks TW and all you guys for your help and patience, I think I got it now. Now how do I get my wife to stop with the honeydo lists? Thanks agian John

Okie (and bernie), Yes , I am confused, Havent work with endoers with this type of problem. The illstration is correct. So when you mean rollover , when its reaches the software overflow count , it will automaticilly rollover to zero? and that rollover count would be the number of count on the encoder ( in your ill, its 720 but the roll over would be 575) That count (575) would be placed in the Overflow value in the HSC parameters? thank you again for your help and patience Mr JJ The problem Im trying figure this out and dont have any hardware to play with

Its not the number of count is, whatever the encoder is ( 360 counts , or 100 counts or whatever I choose) The issue is the starting point, or the zero, The shaft does not stop at the same position, it stop minus 72 degrees after each single cycle hence I have to start it at at that different position So Im looking to offset or reset the HSC to start my counts at zero. John

Thanks Paul for your reply. My problen is that the HSC has to start its "starting zero" -72 degrees from its pervious starting zero. This will happen for 5 cycles, then starts its original starting zero. The cause being the shaft is an odd ratio to the linear motion. I want to use the HSC to shift a BSL and to activate 2 inspection windows in a cycle. I figure I either offset the "starting zero" or I have to use 5 different degrees to work the logic. Does that make sence Thanks again for your help John (Mr JJ) I would recommend avoiding resetting the HSC accumulator regularly while the system is in motion. You are better off to set up the counter so that it resets itself. Resetting the HSC from PLC code can result in missed pulses which could accumulate and end up being a big error over time. I am not sure I exactly follow why you would need to reset the HSC, other than to initialize it after doing maintenance. Even if the encoder is not attached to the main drive shaft and at an odd-ball ratio, you should be able to calculate how many encoder pulses per main shaft revolution you get, and set up your counter accordingly. I believe you can simply set the overflow and underflow values to the numbers you need so that it rolls over when the main shaft rolls over, regardless of the position of the shaft that is driving the encoder. That's the beauty of using a PLC with an encoder interface. You can program the PLC such that 9564 counts is exactly 3 feet of conveyor movement or 360 degrees of main camshaft rotation, or whatever else you want. Later on, you can decide that the enoder will do better at a different location, and change your scaling with ease. Doing it that way means that your ratio needs to be exact (whole encoder counts), and there's no slippage. If the number of counts with reference to the main shaft is not a whole number, or there is slippage, then I would recommend using a limit switch as a reset pulse rather than relying on PLC code to get you accurately back to zero. Hopefully I understood your question correctly Paul

We are adding a plc onto a system that is all mechanical (cams, motors and etec.), We are going to put an encoder and plc (ML1200, internal HSC). The "zero" has to be offset every -72 deg. after 5 cycles it will be at its original "starting " zero. It is a in-line assembly system. The cycle linear distance is a 1.5" pitch vs. the 1.2" radial motion, the only shaft that we have to drive the Encoder / HSC. There is no 1:1 In Line linear / circular shaft motion. What would be the best way to accomplish this. Can the "zero" positon of the HSC be offset (reset to zero) from a discreate Limit Ss., or would it be better to go through the PLC/HSC software. And after each index progression the "zero offsets (reset to zero) -72 degs. Thank you in advance for your help John

That was the second part of my question, How would I figure out what min. frequency i would need? How would I calculate that? The cycle is less than 2 seconds and the sensor would see it approximilty .25 sec and be on for a .25 seconds

Hi, Looking for recommendations using an Allen Bradley PLC for a simple project 2 or 3 inputs ( 24Vdc NPN) and 2 or 3 outputs (24Vdc NPN or relay) and I want to use an encoder with an internal HSC. The speed of the application is slow, 2 second cycle time. Which PLC would probably be the best to use? I thought the ML1000 should do the job? Also how would one figure out what HSC one would need with respect to the speee of the system rpm and the HSC? Where would I find the calculations? Thank you for any help you have provided John

Mickey, I dont have a need for it now, but can I use the same instruction (SCP) for a analog output (1762-IF20F2) ? Mr JJ

Thank you Mickey Just looking at the .RSS you sent me, looks very simple. Thanks again for your help...MrJJ

Using the ML1200 1762-L24BWA PLC, Dont have any of the hardware yet, just trying to beat the learning curve The sensor measures liquid height ( small S/S tank ) Hopefully measures low high points to start/stop a pump and when tank is empty, turn on an alarm. Engineering Units all i know is its an analog signal putting out 4 -20ma. I dont have any ladder logic as of yet. Im just looking for a turtorial or examples how its done. Correct me if Im wrong , I would assume there all program basically the same? Thank you

Hi, I never used an analog I/O card in any project I.,ve done, but now I going to use an 1762-IF4 9 (4 -20ma). Im looking for examples of prgramming the 1762-IF4. I will be using a Keyence Ultrasonic sensor analong output. I like to play with it and learn but I'll be doing this on site. So if anyone can direct me to a turtorial or example program for the RSlogix 500 i would greatly appricate it. Thank you in advance for your help Mr JJ

They did plug it in all the way, but the fault light is still on. And yes they did recycle power a few times. Sorry for the mis-spelling before. John

When they pulled the card and then turned the power back on, it fault becuase the card wasnt in all the way and i dont have S:1.8 set to 1. so the only wat i can reset the falut is with a PC/RSlogix500 and then i will set bit S:1/8. John

They pulled the card out to check the wiring (for vwalidation reasons) and just didn't push it all the way back in. And then forgot about it and turn the system back on. And nobody there has a PC with RSlogix on it. So i just wanted to know if there was any way of resetting it with out a PC. With out changing S:1/8 to 1 , I assume there isnt , so I guess I''l have to take a ride and do it .... reset the fault and set S:1/8 to 1 so it doesnt happened again. Thanks for your help john