Hi everybody! Does anybody know what is the difference between ONS and OSR intructions in RsLogix500? I would like to know if it's allowed to use branches before the ONS instruction, OSR doesn't allow it. Thanks a lot, Mildred Henriquez Automation Dept. Zanchetta e C. s.r.l. e-mail: [email protected]

 

Go back with me in time about 10 years to the beginning of the Allen-Bradley SLC-500 line of processors... The PLC-5 already existed, and the SLC-500 was designed by a different group within A-B. The PLC-5 had three one shot instructions: ONS, OSR, and OSF. The then-new SLC-500 processors had only the simplest one shot instruction, equivalent to the PLC-5 ONS. But for some reason that remains a great mystery to me, that _same_instruction_ in the SLC-500 processors was, and still is, called OSR. Now move forward to the late 1990's. The Micrologix 1200 and 1500 are introduced, and lo and behold, they support the same three one-shot instructions the PLC-5 does, and they are called the same names as the PLC-5! The RSLogix500 software is used to program the SLC-500 _and_ Micrologic processors, so it supports all three instructions. However, depending on the processor you select, the unsupported instructions won't be available, and OSR will be interpreted differently. The SLC-500 OSR / PLC-5 & Micrologix 1200&1500 ONS is a single bit instruction. The OSR (rising) and OSF (falling) instructions have separate storage and output bits, and aren't supported in the SLC-500 and Micrologix 1000 processors. See the instruction set reference manuals or Instruction Help in RSLogix for more info. Hope that helps, Eric M. Klintworth, PE Columbus, Ohio

 

Why do you say OSR doesn't allow it? What processor are you using? What Logix version?

 

ONS is an input (in the left side of the ladder)....while OSR & OSF is an ouput (in the right side of the ladder). that's the different. Micrologix1500 treat OSR different way with SLC5/0X.......but ONS instruction is likely the same as OSR in the SLC5/04.... Why ?? don't know ???? > Why do you say OSR doesn't allow it? > What processor are you using? > What Logix version?