JovialProgrammer

Here is my implementation of the traffic intersection exercise for ProLogix.  Some people use SQO's but when you have to alter how the program runs due to random inputs like a pedestrian push button that can occur at anytime it has it's limits. My program uses a single timer and each light has a designated time interval in which it is lit.  The random inputs like pedestrians pushing the button or a car entering a loop while the light is red simply alters the timing.  There is one functionality that I still need to implement in the program and that is when you push the pedestrian button it needs to "hold" over until the next cycle if you press it too late.  What I have here should be sufficient for you guys to get some ideas though that doesn't involve SQO's or multiple timers.  Though I will admit multiple timers would probably be more versatile. Inputs: North West Crossing Button North East Crossing Button North West Loop North East Loop Outputs: ...

Siemens is very large with a very large scope of operation, as such they have good market reach.  This means good documentation and usage in the field so if you have a problem it typically isn't too hard to find the solution.  That being said they make it very hard to even get a look at their tech if you are looking to expand your knowledge or do some basic research.  Try downloading a trial version of their development software and you'll know what I mean.  Here are their current main offerings for PLCs: Simatic S7-1200 - Compact/Small "Basic controllers are the intelligent choice for compact automation solutions with integrated communication and technology functions. They are available in standard and failsafe versions." Simatic S7-1500 - Advanced "You’ll achieve the highest productivity and product quality in your production process by using SIMATIC S7-1500 with its fast backplane bus, PROFINET performance, shortest reaction times, and a command processi...

Allen Bradley is a large player in the industrial automation scene.  Siemens is their only real  competitor in this regard.  They have a wide variety of products in various model lines and their products is typically where the vast majority of PLC programmers first get a taste of PLC programming.  Since they are so widespread there is good support and documentation for them. Their proprietary development software is predominantly RSLogix which includes 500 and 5000. RSLogix 5000 being very powerful with some very nice functions that should be included in all development environments if you ask me.  It is pricey though...anywho, here are their current product lines: ControlLogix - Large Scale: "Our ControlLogix® control systems use a common control engine with a common development environment to provide high performance in an easy-to-use environment. Tight integration between the programming software, controller, and I/O modules reduces development time and co...

The general public knows Mitsubishi as a car manufacturer but like many Japanese car manufacturers they have other branches in the industrial sector and Mitsubishi Electric is one of them.  Their line of controllers are called MELSEC series.  As of this writing these 7 listed below are their staple series but they do produce a few application specific PLCs like for robots: MELSEC iQ-R  - Med-Large Scale: "A next-generation programmable automation controller (PAC), the    MELSEC iQ-R Series incorporates a revolutionary high-speed system bus that improves productivity through advanced performance and functionality." MELSEC iQ-F  - Small/Stand alone: "Designed to provide outstanding performance and superior drive control, the MELSEC iQ-F Series is a high-performance compact-class controller with a rich assortment of integrated functions." MELSEC Q  - Med-Large Scale: "The first to incorporate the multiple CPU architecture, the MELSEC-Q Series wide-ra...

What is it? A programmable logic controller, or PLC, is a type of computer that has been adapted for use in more rugged situations that require high reliability.  For instance, industrial manufacturing and automation where you don't want your stuff to blow up or have robots chucking heavy car parts across the building. Extreme heat/cold, moisture, and or shock are only a handful of conditions that can exist in these environments and as we all know, regular computers normally choke under such conditions like when you wanted to ask your crush to senior prom.  Generally speaking though, most run of the mill laptops and desktop computers blow the doors off of PLC's when it comes to raw computing potential and performance but that is in exchange for a rather unstable system though some high end PLC's are pretty on par with modern personal computers.  Ever had your computer crash and you lose all your work?  Or a program keeps freezing up?  Both those things are i...