Andrei IRL
Senior Member
Hi everyone.
I am designing a controller for which is important to stay within programmed parameters.
The Controlling Picaxe (CP) will be sending a high signal on one of the pins for the length 100ms (the time will be adjustable between 40ms and 120ms in the final code) at a time when two button are pressed.
It is important that the signal does not significantly exceed the 100ms time (staying high) and goes low after.
To do this i was thinking to use a second Watch Dog PICAXE (WDP) as a watch dog with the controlling one.
Here are the ideas i have so far:
1. Use WDP to supply power to the CP using a PNP transistor.
2. Use WDP to monitor the HIGH Signal and if its more then 100ms cut the power to the PNP transistor and liight up RED LED.
3. Use some sort of pulsing signal within Main Routine in CP and use WDP to monitor this signal, if signal no received then cut power to PNP and light RED LED.
-I am not sure what else would be good a good practice for a watchdog set up.
-Are there any hardware additional functions that can be used to monitore Controlling PICAXE?
-Would it be more beneficial using i2c set up and have?
Basically i would like to build as much Fail-Safe as possible, in the even Controlling PICAXE fails for any reason i would like to cut the power to it.
All suggestions are welcome.
Thanks very much.
I am designing a controller for which is important to stay within programmed parameters.
The Controlling Picaxe (CP) will be sending a high signal on one of the pins for the length 100ms (the time will be adjustable between 40ms and 120ms in the final code) at a time when two button are pressed.
It is important that the signal does not significantly exceed the 100ms time (staying high) and goes low after.
To do this i was thinking to use a second Watch Dog PICAXE (WDP) as a watch dog with the controlling one.
Here are the ideas i have so far:
1. Use WDP to supply power to the CP using a PNP transistor.
2. Use WDP to monitor the HIGH Signal and if its more then 100ms cut the power to the PNP transistor and liight up RED LED.
3. Use some sort of pulsing signal within Main Routine in CP and use WDP to monitor this signal, if signal no received then cut power to PNP and light RED LED.
-I am not sure what else would be good a good practice for a watchdog set up.
-Are there any hardware additional functions that can be used to monitore Controlling PICAXE?
-Would it be more beneficial using i2c set up and have?
Basically i would like to build as much Fail-Safe as possible, in the even Controlling PICAXE fails for any reason i would like to cut the power to it.
All suggestions are welcome.
Thanks very much.