About the 8020-SCP-401
8020-SCP-401 is a Model 400, 4K RAM Processor without a floating point that is manufactured by Square D. The scan speed for this processor is 4.1 milliseconds per K of Boolean logic and 7.9 milliseconds per K of nominal logic.There are many status indicators on the front panel of the processor. The RUN light is green, and when ON, it indicates that the processor is operating on I/O’s and scanning the ladder diagram program. When the RUN light is flashing, the processor is in Disable Outputs mode. The Halt light is red, and when ON or flashing, the processor is not scanning the ladder diagram program and has halted its execution.
The MEMORY light is red, and when ON, a memory error has caused the processor to halt. The FORCE light is red, and when ON or flashing, the ladder diagram program has been overridden by one or more I/O’s being forced into ON or OFF mode. The I/O light is red, and when ON, a malfunction in the I/O system has caused the processor to halt. The I/O system is regarded as an I/O or register module that the processor controls in a rack assembly. The BATTERY LOW light is red, and when ON, the onboard lithium battery charge is low. The WRITE PROTECT light is red, and when ON, the internal write-protect jumper is in the NO PROGRAM position and/or that the user memory is protected by the key switch positioned in the RUN mode.
