Programming and File Management Part 2 Robot Construction Programming and File Management Part 2

Subroutines Subroutines are a sequence of instructions grouped together to perform an action that the main program accesses for repeated use. The purpose of using subroutines is to reduce the lines of code in a program and make it easier to write programs. Examples of subroutines are opening or closing grippers, a tooling change, alarm response actions, and other actions that support the operation of the robot.

Be sure to create subroutines as a global function instead of a local function. Global functions are variables, subroutines, and other code or data accessible by any program that you create on the robot. Local function means that only one program can access the data.

Some systems call global subroutines macros. A macro is a single instruction or specified button used to generate a sequence of instructions or other outputs. Determine what tasks should be turned into subroutines before writing the program to save time and effort.

Writing the Program You must know how your particular robot works, how the controller organizes information, and how to build a program for the specific robot that you are using. Common options that you need to be aware of are naming the program, determining the program type, designating the frame, picking the proper tooling, and designating offset tables to reference.

The reference frame defines the zero point for the work envelope and is the point from which the robot defines all other positions. If you change the reference frame after creating the program and saving points, there is a high probability that your taught points will change. When working with a system that has multiple tooling, make sure to select the proper tooling or tooling group.

Common logic commands: And is a logical function that requires two or more separate events or data states to occur before the output of the function occurs. Or is a logic filter where at least one, or more than one, of two or more input events must be true for the output to occur. Nor is a logic sorting filter in which all input conditions must be false before the output occurs. Xor/Exclusive Or is a logic filter where the output is only activated when any one of the inputs is true, but not more than one.

Not is the opposite of the “And” command, in that all the input conditions must be false before the output is triggered. NAnd is the opposite of the “And” command, in that all the input conditions must be false before the output is true. If Then is an advanced logic filter that allows you to set a complex set of conditions to occur before a desired output function happens.

Jump to advances the reading of the program to the designated line, avoiding the execution of the lines skipped. End stops the scanning of the program and triggers the system’s normal end-of-program responses. Call program/subroutine calls up subroutines or other programs to help reduce the lines of code in a program.

Wait creates timed pauses in the program or has the robot wait for a specified set of conditions before continuing with programmed actions. Math functions let you add, subtract, multiply, and divide in varying levels of complexity for data manipulation.

For long programs you should save every 10 minutes The specifics of creating a program, saving points, setting the motion types, creating the logic filters, and calling subroutines and all the other bits and pieces that make up a program depend on the system you are working with.

Testing and Verifying Once you complete your program, you must test it no matter how sure you are that nothing will go wrong. For most systems, manual testing requires you to hold the dead man switch on the teach pendant so you can stop the system immediately giving you the control to keep the robot from crashing or damaging parts. Another good thing is that the system runs at half its normal speed giving the operator a chance to respond if something goes wrong.

In step mode, the robot advances through the program one line at a time and requires you to press a button on the teach pendant keypad before it reads the next line of the program and responds. Continuous mode is a manual mode in which a program runs until completed or a specific button is released.

Some motions in your program cannot happen in the space allotted if the robot moves slowly. Most systems will give you a warning alarm; once you accept or hit whatever is required to authorize the movement, the next movement that the robot makes will be at or near full speed. This is often the case when you make a radical change in the tooling orientation between points or other moves where the axes involved have to turn a great distance.

If you hit yes and do not keep in mind what is about to happen, you could get a nasty surprise, especially if you are close to the robot when this move happens. Anytime you get an alarm on the robot, take the time to read it and determine what the alarm is telling you so that you don’t crash the robot, damage parts, have near misses, and mess up your program by hurrying and ignoring what the alarm said.

Normal Operation When running a new or edited program for the first time in automatic mode, make sure that you watch the robot go through the program a couple of times before you consider it ready to run with limited supervision.

File Maintenance Your programs should be saved in some form of backup such as a Flash Drive, SD card, hard drive, or other storage medium to keep them from being deleted.