We can classify plc into two categories
1- Classification by I/O modules.
2- Classification by application ranges.
1- Classification by I/O modules.
2- Classification by application ranges.
Classification by I/O modules:
1- DISCRETE I/O SYSTEMS.
The discrete (I/O) system provides the physical connection between the CPU and field devices that transmit and receive digital signals.
1- DISCRETE I/O SYSTEMS.
The discrete (I/O) system provides the physical connection between the CPU and field devices that transmit and receive digital signals.
2- ANALOG I/O SYSTEMS.
Analog input modules, are used in applications where the field equipment’s signal is continuous such as Pressure and Temperature.
Analog input modules, are used in applications where the field equipment’s signal is continuous such as Pressure and Temperature.
Analog output module are used in applications which need to continuous voltage or current levels for control. An example of this type of field device is a electric motor drives.
Classification by application ranges
The PLC can be divided into 5 groups shown in blow figure:
1- Micro PLCs are used in applications controlling up to 32 I/O Devices.
2- Small PLCs which controls 32 to 128 I/O.
3- Medium PLCs which controls 64 to 1024 I/O.
4- Large PLCs which controls 512 to 4096 I/O.
5- very large PLCs which controls 2048 to 8192 I/O.
The PLC can be divided into 5 groups shown in blow figure:
1- Micro PLCs are used in applications controlling up to 32 I/O Devices.
2- Small PLCs which controls 32 to 128 I/O.
3- Medium PLCs which controls 64 to 1024 I/O.
4- Large PLCs which controls 512 to 4096 I/O.
5- very large PLCs which controls 2048 to 8192 I/O.
A, B, and C overlapping areas in the Figure reflect enhancements, by adding options, These options allow a product to be closely matched to the application without having to purchase the next larger unit.(extension I/O modules )
