To get this kind of local intelligence, you would expect to have to buy a mini PLC or supplementary PLC and then program it with its own programming software. Opto 22’s SNAP I/O brain does not require programming, all its functions are built in.
The following operations at the SNAP I/O brain level without additional programming:
• Thermocouple linearization.
• Engineering unit conversion.
• PID loop control.
• Temperature conversion.
• Serial device control.
• High speed counting up to 20 kHz depends on the brain and module.
• Analog scaling.
• Quadrature counting.
• Output clamping.
• Gain and offset (calibration).
• Analog ramping.
• Maximum and minimum values.
• Filter weight.
• Analog and digital totalizing.
• Watchdog timeout.
• Input latching.
• TPO (time proportional output).
• Period and frequency measurement.
• Pulse generation measurement.
The utility of free I/O configuration is included with the brain. Once the new I/O is configured, perform required functions, the brain scans its local I/O, and waits for the PLC to pick up the data.
The brain continues to run PID loops and other functions locally if communication with the PLC is lost, so a communication failure does not necessarily cause local processes to stop. If a process needs to be brought t a safe condition in the communication failure event, for instance, pumps or valves turned off, the watchdog timeout can be enabled to monitor communications, and the brain will set outputs to a predetermined level if a failure occurs.
Conformance tested by ODVA’s Test Service Providers, Opto 22’s SNAP I/O is compatible completely with Allen-Bradley CompactLogix and ControlLogix PLCs using Ethernet/IP.
The Opto 22 SNAP I/O that engineers can use now to supplement an Allen-Bradley system is regarded widely as exceptionally reliable, industrially hardened I/O. for instance, its digital-to-analog and analog-to-digital conversion process is less susceptible to noise than other I/O on the market.