PLC detector! Is it possible?

[bAs_gOlD]

Does anyone have any information on using a PLC to build a PI metal detector?

The PLC is a ABB PM564-T-ETH

Onboard I/Os in PM564 CPUs

- 6 DI 24 V DC
- 6 DO (24 V DC, 0.5 A max transistor outputs)
- 2 AI (voltage 0 ... 10 V)
- 1 AO (voltage 0 ... 10 V or current 0 ... 20 mA / 4 ... 20 mA)

Functionality

Digital inputs	6 (24 V DC), can be used as source inputs or as sink inputs
Interrupt inputs	4 (DI0 ... DI3), configurable
High-speed counter	2 (DI0 and DI1), configurable
Digital outputs	6 transistor outputs (24 V DC, 0.5 A max)
PWM outputs	2 (DO2 and DO3), configurable
Analog inputs	2, voltage input 0 ... 10 V DC, can be configured as digital inputs
Analog outputs	1, voltage output 0 ... 10 V DC or current output 0 ... 20 mA / 4 ... 20 mA
LED displays	For signal statuses
Internal power supply	Via CPU
External power supply	Via CPU

[Dai]

Old thread I know, in theory it may be possable, it would depend on cpu instruction time and the speed of your high speed inputs. Some of the PLC's in this family have a 0.08uS instruction time so could procsess signals fast enough, limmited by your hardware input speed. There are PLC's that are capable of 1MHz I/O speed and motion controlers that could handle such signal procsessing. One would still need to apply some external circuit to deal with the high voltage flyback pulse from coil, PLC's wouldnt like this sort of input directly. The unit also wouldnt be very portable, so more for vehicle use.

Dave