Active pin is shown as up arrow and the non active pin is shown as down arrow. A 40×4 character lcd on status board is used to show the plc status visually. Two latches store input status and the remaining two store the output status. Four 74ls574 8-bit latches on status board are used to store the input and output status of plc. Status lcd board purpose is to show the status of the plc inputs and outputs. Microchip Pickit 2 Programmer made at home – Diy Project I have a separate tutorial on pickit 2 programmer made at home. Dip switches are installed to prevent the controller pins from interference by the pickit 2 programmer circuit. When ever a new logic is desired to be downloaded in the processor, switch on the dip switches. Icsp interface of pickit 2 programmer is connected with the pic16f877a microcontroller using DIP switches. Pickit 2 uses icsp interface to program the target microcontroller. Pickit 2 is a programmer by microchip used to program its pic microcontrollers. LM7805 regulator is used to convert the +12v to +5v for power supply to microcontroller, opto couplers and uln2803 relay driver.įor programming the board/microcontroller/pic16f877A pickit 2 programmer is made on the board. Whole board is powered using a +12v dc supply. Core plc board processor is pic16f877a working at 20MHz. Relay coils are directly connected to the uln2803 output and does not need the fly back diodes, since they are build inside ic. It has built in fly-back diodes for driving coils and prevents from back efm damage.
Uln2803 can sink 500mA of current from a 50V power supply. They are derived from Uln2803 Ic.Uln2803 is an 8-channel darling-ton array high output current ic. At output side i used 16 relays for switching heavy loads. Diodes are used at inputs from reverse polarity protection. Optocouplers are used to protect the circuit/processor from heavy loads damage.
#Pbp3 serial displays series#
Pic10f series microcontroller based Project List of PDFĬore plc board is comprised of 16 digital inputs and 16 digital outputs.
#Pbp3 serial displays pdf#
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