Power module
Wonder why there is no schematics. No time for this kind of work. The
good thing about digital design is that you don't need schematics. only
concepts in your head. This is true also for semi-digital design like
this power module which has the following capabilities required for
heating regulation:
- Driving of four mixing valve motors with 2 minutes for full cycle.
The circuit consist of 74HC595 shift
register for driving optocouplers with zero crossing triac
outputs TLP3063. Some snubber RC circuitry was added for
protection.
- Oil burner and 7 circulator pump relays. Driving is with ULN2803
transistor array. 74HC595 is used for serial shifting of data and
is cascaded with mixing valve motor shift register.
- Three 240 VAC input signal sensing with
4N27 opto-couplers. Output is integrated with RC circuit. This is
used mainly for counting oil-burner working time and detecting
error line from burner. Low current LED is connected in reverse of
OC for limiting reverse voltage of OC and signaling the
line.
- RS485 CSMA communication network with RS232
to RS485 interface for direct computer connection
- AC filter, transformer, 5V linear voltage regulator for this and
other modules. 40 pin connector is connected to SAB80535 CPU
module
- DS1820 digital thermometers line
The whole PCB is in PCB 1.6 format.
