Joseph 0028

That is true in general, but for immediate active and passive homing, there will be no motion. Both does the same of setting your entered home position to the actual position. I think, active homing enables the axis, and passive you can do even with axis turned off. I will test it myself next time when I am onsite...  

That Rockwell post answers nothing, its just generic explanation from help. 

@pturmel that answers it, thank you. 

So we need to unlatch these bits before every motion command ?  Cause i have seen programs without unlatching these bits, but they still work fine. So just wanted to know if its really necessary. 

Its Control Logix L84E, and Logix Designer v32. Application is linear motion, forks that goes forward and reverse. We don't use any sensor or offset to home. And strangely in different versions of the program, I see different homing methods, like one program its active immediate and another its passive immediate, so just wanted to know the difference.   

I have seen some programs in which they manually unlatch all bits like in figure 1, and in some programs they don't do that.  The instruction help page, ladder execution says that in pre-scan .EN, .DN, .ER, .IT bits are cleared to false So do we need to unlatch all these bits before giving a motion command like MAM ?  

 What is the difference between Active Immediate homing and passive immediate homing ?   Does Motion servo axis have to be turned ON for active immediate and turned OFF for passive immediate homing ?.

yes, you are right. Actually IO_Rmc1:O.Data[0] is an array of Real[124], and we have the formula IO_Rmc1:O.Data[0]=(IO_Rmc1:O.Data[0]+1)MOD1000. So I believe we increment IO_Rmc1:O.Data[0] from 0 to 999 and then repeat ?

I have the below formula in CPT instruction (not able to attach any pics)...  IO_Rmc_Data = (IO_Rmc_Data+1) MOD 10 What does MOD 10, MOD 1000, MOD 10000 do ? On help it says it stores the remainder of division, but here its doing something else. 

I am not an expert, but if you have testing time, you can try using MAPC and MCCP, where one axis can be master and one can be slave.  You can study the instructions and try using them. 

Hello Folks... The pictures show it all... I just need to produce a one-shot inside the IF...THEN, and the Oneshot's input bit goes from 0 to 1 as you see from the trend, but the output bit is not going to 1, or giving a pulse ? can anyone help me understand why i am not getting a pulse in this code ? And is there another easy way to get pulse inside IF...THEN without changing the condition which activates the if loop ? Thanks in advance for your time

Lets say i have a PLC, with a name PLC1 with IP/Subnet of 10.125.34.243/255.255.255.0 I have to communicate this PLC1 with 2 other PLC's, PLC2 and PLC3 PLC2 with IP/Subnet of 10.125.34.10/255.255.0.0 PLC3 with IP/Subnet of 10.125.46.10/255.255.0.0 I imagine that, all these three are in different subnets, and so there should be no communication at all, but when i tested it, PLC1 to talking to/from PLC2 and not PLC3.  anyone know the answer to this ? How does it talk to PLC2 with different subnet, but not PLC3 which is in different subnet as well. 

Excellent... that worked... Thanks brother.... 

I was given a logic to program on AB logix designer - controller is AB 5570 - L73 - Language is Ladder Logic There are total of 5 photocells and a motor to run 1. If none of the photocells are on - then run motor on 200 FPM 2. If any one photocell is on - then run motor on 180 FPM 3. If any two photocell is on - then run motor on 160 FPM 4. If any three photocells are on - then run motor on 140 FPM 5. If any four photocells are on - then run motor on 120 FRM 6. If all 5 photocells are on - Then run motor on 100 FPM  The motor speed can be just on a move block with Motor speed tag, as this is just a test program... Can anyone help me with this logic, whats the efficient way to program...  I can do it for condition 1 - none of the photocells on and for condition 6 - all 5 photocells on, but don't know how to do it for the rest... 

Hello Guys, I am doing this simple project to measure repeat length. I am using MicroLogix 1200 PLC, and encoder and contrast sensor.  Logic is very simple, the encoder counts gives the repeat length, and when the contrast signal gives a signal, the encoder counts (HSC:0.ACC) should move to N7:0, and then should reset... So this N7:0 gives the repeat length... Now the HSC accumulator is working... I configured the Function files, and HSC0... Please see the pic...   But the move and RAC are not working... Any help much appreciated...