text: <s>[INST] STEP LOGIC IN DRIVE Summary: HOW TO CONFIGURE DRIVE IN STEP LOGICcan anyone upload a document by which step logic function in Allen Bradley drive can be understood (in easy way)? i have read manuals provided by rockwell but it is very difficult to understand the procedure. thanks. [/INST] Yeah, you are absolutely correct - the step logic as defined in the PF525 manual is as confusing as one can get. I JUST finished programming a 525 for step logic. I suggest, rather than trying to puzzle it out on paper, instead use Connected Components Workbench. Start it up, put a 525 into the project organizer, then go to the wizards tab (or branch of the tree, depending on which version of CCW you're running). In Wizards for this drive, there are two for step logic - one for position and one for velocity. Running the velocity wizard opens a welcome splash screen, with familiar Back/Next buttons at the bottom. Clicking Next takes one to the common settings branch of the wizard. The screen is fairly self-explanatory, you set speed references, accels, and IO configurations necessary for step logic to work. Here, I configured. In my case, I'd configured DigIn TermBlk 05 to be Logic1-In and DigIn TermBlk 06 to be Logic2-In. I set SpeedRef1 for Pot, SpeedRef2 to Step Logic, and SpeedRef3 to Ethernet/IP. Clicking NEXT takes you to Step 0. Step logic always starts with Step 0. Once here, you configure a few things in the ACTION tab (near middle of the window). In my case, Step 0 was a decision branch; I didn't want anything to actually output. I selected NO Output (drive doesn't do anything) Use Accel 1 (meaningless based on the previous setting), and Logic Output state = off. Click over to the Logic tab on Step 0 - this is where the decision branch occurs. There's two decision branches here. You get to go to the next step (step 1) based on what you configure for the first branch. You get to go to some OTHER branch that you can define if different logic is true. In my case, I wanted to go to Step 1 if LOGIC1-IN was true, or go to Step 2 if LOGIC2-IN was true. Step 1, on the Action Tab, I configured direction Rotation Forward, use Accel1, and logic state to be off. I set preset frequency to 5 hz, and also set the time value to 0.1 seconds. Step 1, on the Logic tab, I set Go to Next Step to be NEVER (don't step), and configured the OR choice to be If Time expires and Logic1 is ON, then END-Normal Stop. Step 2, on the action tab, I configured direction Rotation Reverse, Use Accel1, and logic state to be off. I set preset frequency to 5 hz, and also set the time value to 0.1 seconds. Step 2, on the Logic tab, I set Go to Next Step to be NEVER (don't step), and configured the OR choice to be If Time Expires and Logic2 is ON, then END-Normal Stop. That's all that I needed, so Click Finish to close the wizard. If you go to the drive's parameters in CCW, and select the Logic branch in the pull-down, you should see the steps now configured. For whatever reason, the User Manual shows the steps being configured in 4 hexidecimal digits, but CCW displays the step values in binary by default. Dumb choice by Rockwell. Click on the value box for Step 1 and it shows has hex, and you should be able to decode the 4 digits shown by looking at the user manual table for parameters 180-187. CCW makes it far easier to configure step logic than doing it by hand. The logic I outlined above SHOULD make this drive do this: If Input input terminal 5 is activated (by a pushbutton), the drive will run forward at 5 hz for .1 seconds, and then normal stop (not coast). If input terminal 6 is activated (by a pushbutton), the drive will run reverse at 5 hz for .1 seconds, and then normal stop. The drive should index a small distance with each button push. This should allow the operator to bump the drive by the same distance each time without relying on operator dexterity on the buttons. Each bump requires a new button push. The customer's desire is to have crude but accurate positioning capability without the expense of encoder feedback, higher-priced drives, etc. \\n </s>