If you have come across a Pico PLC, you will appreciate its simplicity in performing logic tasks, timings, counting and real time clock functions in such a small package.
So what is special about the Pico controlling device? You won't fail to observe how suitable this little device is when used in relay replacement purposes which they are perfect for. Your typical controller will manage your parking lights easily with no fuss. Plus since they offer expansion modules and device-net communications they can grow to meet enhancements to your original application.
The Allen Bradley's Pico PLC is their smallest controller offering. You can get in many configurations. From 12 to 20 built in DI/DO, ac/dc power, analog inputs,and a LCD display. It can also be expanded to 40 with four soft input keys. For improved efficiency, two analog inputs are provided with a VDC of 0 to 10. A total of 16 timers and counters are put in place to monitor the device with full 4 real-time clock instructions.
IF you choose the models with the LCD display and keypad, you can program and run the device without a computer for programming it. If you really are not in touch with the keypad idea, configuration software known as Picosoft is available.
Picosoft programming software is easier to use than the built in Display/Keyboard comb for tasks that are longer and require many lines of coding. On its functionality, it is a perceptive application that helps you build, save, replicate, document and even move the Pico circuit diagrams to the Pico PLC. Transfer of diagrams from the computer to the PLC controller is straight forward and the user can even compare diagrams from the PC and the PLC device.
If you want more features on your Pico controller, try the Pico-GFX model. It is more advanced with I/O counts of 16 to 40. It has the two available analog inputs with an extra analog that serves as the output. Pico-GFX is your ideal controller in versatility and can perform data logging operations, Math expressions, PID Loops and even HMI. The memory has been widened to include 12MBs for HMI operations.
A strong competitor to Allen Bradley's Pico controller is the Siemens LOGO line. Similar in appearance, application, and expandability with the main difference I think is their programming environment. Theirs is Function Block programmed. This might be a better choice for you if never have used ladder logic programming before, since I feel it is more intuitive.
An very inexpensive Pico PLC from a Taiwanese company Array Electronics is an excellent choice for a small project with a very small budget.
Noteworthy is their free plc programming software is Function Block based rather than the typical Ladder logic. Other features are expandable to 122 I/O, remote control, wireless module and program simulation. You can debug your program before ever connecting to your PLC. This could be useful if someone else is constructing the PLC enclosure and the actual machine that the PLC will eventually control.