About the 8020-SCP-544
8020-SCP-544 is a Model 500, 2.5K RAM/5.5K UV PROM Processor that is manufactured by Square D. There are a number of control registers present on this processor. Control register addresses 8001-8160 are used when the system has more than one local interface module. Control register addresses 8161, 8162, and 8163 communicate with the local interface module. Control register address 8162 is channel 1 of the local interface module, and 8161 is channel 2 of the local interface module. 8163 is the error code control register for the local interface module. 8164 is the I/O group safeguard. 8165 is the register safeguard. Registers 8166, 8167, 8168, and 8170 are used by the processor internally. 8169 contains the BAUD rate code of the processor communication channels. 8171 contains the remainder of the most recent division performed by the ladder diagram. 8172 is the processor scan time in milliseconds. 8173 is the end fence address. 8174 is the begin fence address. 8175 contains the last error number which occured, or the most serious error if more than one has occured. 8176 and 8186 contain individual bits that flag certain conditions. 8177 to 8184 are used by the processor internally. 8185 is a binary number that represents the number of racks defined in the Rack Addressing mode. 8187 contains the number of rungs entered into the memory by the user. 8188 is a number that represents the processor type and firmware revision. 8189 to 8192 are used by the processor internally.
