THE Mitsubishi Alpha2 family of Programmable Logic Controllers (PLCs), available from NHP , offers a large range of features and functions that outweigh its size and cost.
A built-in calendar and Real Time Clock with automatic summer/winter time switching allows up to 1200 clock/calendar-activated on/off switching commands to be programmed.
The program memory is stored in an EEPROM that does not require battery backup, while the data memory and the Real Time Clock are maintained for up to 20 days of power outage.
A very handy feature allows alarms and process status information to be sent to multiple mobile phones via SMS and SMS can be sent to the Alpha2, to turn on/off outputs, or to change a set point value.
Temperature transducers are available for PT100 RTDs or K-Type thermocouples and up to ten analogue inputs can be measured with 9 bit resolution. Auto-tuning PID and Schmidt trigger control is also available.
The inputs can detect switch pulses as fast as 1KHz, making it suitable for use with an incremental encoder.
The large backlit LCD screen allows display of process data, alarms and status messages.
Programming of the Alpha2 controller is achieved with user-friendly software, or via a set of eight pushbuttons surrounding the LCD screen.
The software program is easily learned and allows the user to simulate and test programs, monitor the process online and to provide simple process visualisation.
The smallest Alpha2 has a footprint of 72mm x 90mm, allowing it to fit nearly anywhere. It can operate in ambient environments between -25°C and 55ºC.