viveklengade
Member level 1
please tell me the hints for designing the PIC 18F452 based system.
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viveklengade said:basically i want to design the general purpose system for the motor(pump) in the farm. which include
1. Over volatge protetction
2. under voltage protetction
3. over load portetction
4. dry run portection
5. measuring the total run time of pump
6. preset on/ off of pump
i am using the I2C, for serial EEPROM 24c04 and RTC DS1307, lcd display 8*2, and 4 keys. tell me is this suuficient or i have to give some more info.
thanks and regards,
vivek lengade
ravimarcus said:18F452 is an overkill for this application. Use an 28 PIN or 18PIN device.
1. When you have EEPROM inside the PICmicro, there is no need to use external SEEPROM unless you want to store large amounts of data.
2. The RTC can be realised using TMR1 with a 32768 Hz crystal.
3. Over & under voltage protetction can be realised by detecting the mains voltage.
4. Over load portection can be done by sensing the motor current (jammed rotor, etc).
Rest is in software.
Cheers
Ravi
FoxyRick said:Your points 1 and 2, while not incorrect, might not be appropriate for this situation. The run hours of a motor is important, and should the PIC be swapped out for a firmware update, or be reprogrammed, or die, the flash memory might be lost, thus losing the current run hours. I would use the EEPROM myself for this.
Keeping the RTC in software is easy even without the 32768Hz crystal. I have one running with an accuracy of better than 1 second per month after simple initial adjustment. However, if the power is lost, the time needs to be re-entered for the timed operation of the pump and this might not be appropriate for the application. The addiditon of an external, battery or supercap powered clock eliminates the potential problem.
viveklengade said:hi guys
i started working on PIC 18f452. but i want to know that is any body used on chip adc? if yes how he is used the same for an application?