The higher switches labelled "up" and "down" are SPST momentary microswitches which are closed and held when the blind is in that position, and are released as soon as the blind moves from that position.
correct. I would call them "limit switches" but I suppose "microswitch" is just as correct. They are Normally Closed (NC) and are opened when the blinds reach that position.
I've used yenka for about 5 min before I trashed it, so I wouldn't be able to explain anything regarding the program or simulation, but I'll give you a rundown how the circuit should work:
Initial conditions:
1. toggle switch is on
2. Blinds are all the down position, resulting in:
a. "down" limit switch is open.
b. both relays are inactive
3. no buttons are being pushed
The blinds will stay at rest in the down position indefinately, with no power being drawn by the circuit (negating the need for the toggle switch, unless you have other resons for it to be there)
You press the Down button:
1. nothing happens because the "down" limit switch is open. The only other path for current is through the diode which is in parallel with the limit switch, but that diode is reverse biased so no current flows.
You press the Up button:
(description provided in conventional flow)
1. incoming +12V power goes through coil of the relay on the right, and through the Up button, to ground. This actuates the relay.
2. Since the relay is now actuated, it's COM terminal is now connected to the NO terminal, thereby giving its own coil a new path to ground. So you can release the button and the relay will stay energized
3. The motor also has a path to ground now the relay is energized. Incoming power flows from the NC terminal of the Down relay to the COM terminal of the down relay, through the diode (forward biased now) which is in parallel with the "down" limit switch, through the motor, through the "Up" limit switch, from the COM terminal of the Up relay to the NO contact of the Up relay, to ground.
4. The relay coil and the motor share the same ground connection point, which is upstream of the limit switch. So when the blinds reach the up position and the "Up" limit switch is opened, the relay will switch off, along with the motor
5. You are now back to initial conditions, drawing no power.