About the 8020-SCP-312
8020-SCP-312 is a Model 300, 1024 Word Standard Processor with RAM that is manufactured by Square D. There are a number of instructions that can be represented on the processor. The Contact instruction represents the ON or OFF status of an input, output, internal relay, or register bit. The Coil instruction means that an output is connected to the processor. The Internal Relay instruction represents the control relay function. The Latch/Unlatch Relay instruction duplicates the action of a mechanically held latching relay. The user must sequentially program latched and unlatched rungs because the second latch programmed will override the first. The Transitional Coil instruction is an internal or external coil that energizes when the logic transitions from open to closed. This process requires two consecutive I/O addresses: one to record the transition and one to remember the last state.
The Master Control Relay instruction allows the logic to function. When this instruction is off, the logic functions and outputs are disabled. The Timer instruction can store values that range from 0 to 9999, and it allows for delay and interval timers. The Counter instruction has standard UP, DOWN, and UP/DOWN counters, and it is possible to cascade counters. The Synchronous Shift Register instruction can shift individual bis of a storage register in either a forward or reverse direction. The user may shift 1, 8, or 16 register bits at one time. This instruction replaces drum switches. The Asynchronous Shift Register instruction loads data into the FIFO stack. The data then exits via the last zone of the stack using IN and OUT commands (respectively). This is useful in conveyor and alarm applications.
