About the 8020-SCP-644
The 8020-SCP-644 is a Model 600 Processor unit from Square D as part of the SY/MAX 8020 series of products. The 8020-SCP-644 processor is classified as 26 K RAM/UVPROM unit with Floating Point.
The Model 600 processor units have a few significant differences from its Model 400 predecessors, such as a slower scan time by about 10% and an increased current requirement to 5500 mA at 5 Volts. Additionally, the Model 600 processors have a physical size that is about 2.5 inches deeper than the Model 400 processors.
The 8020-SCP-644 processor has eight LED status indicator lights running vertically down the front. The first one, which is labeled as “RUN,” is green, while the other seven LED lights are red. The remaining lights are as follows in order: “HALT,” “MEMORY,” “FORCE,” “I/O,” “BATTERY LOW,” “WRITE PROTECT,” and “PEER COMM ERROR.” Below this series of indicator lights is a small door which is designed to give the user access to the battery. Below that battery door, there is a small key switch. The key switch has four positions: “RUN PROGRAM,” “RUN,” “HALT,” “DISABLE OUTPUTS.” The “RUN/PROGRAM” position executes the ladder program but also allows changes to be made to the program while it is running. The “RUN” position has a similar function, except changes to the program while it is running is not permitted. The “HALT” position does not execute the ladder program and every single output is shut off. The “DISABLE OUTPUTS” position executes the chosen ladder program but the outputs are still shut off. Below the key switch, there is a small port labeled as the “PRGMR CHNL 1.”
