Laying out the electronics
Posted: Mon Dec 24, 2012 6:38 am
I am deciding where to put all the things in the electronics bay. Here are two possibilities. I'll call them Configuration A and Configuration B. First, here's A.
And here's Configuration B.
The two configurations have some things in common. The main power plug is always at the back right corner (not shown). The mains power distribution block, represented by a silver bow, is right in front of it. The PC power supply is along the side of the box. I will cut a hole in the skin to let its fan breathe. The water pump is not shown. It will be outside the chassis. The laser power supply is not shown. It will be on a shelf above all these bits, at the same height as the laser tube. So there are really three components to place.
The air pump has power and air in and out. The air outlet is the brass barb on the end. The air inlet is a black screw fitting sticking out the side of the opposite end. I powered on this air pump for the first time today. It sounds like a freakin' jackhammer. I want a quieter pump. But its connections are very simple.
The Raspberry Pi is the front end processor. It will have these connections.
The Azteeg X3 is the real time processor. It will also handle manual mode operations. It will have lots of connections.
So. Back to configurations A and B.
Configuration A puts the CPUs up front where they're near the control panels and the PC power supply's output, but they're far from the back panel and the sensors and motors in the back. In configuration A, the Y cable carrier would exit toward the front of the chassis.
Configuration B puts the CPUs closer to the rear. It is possible to reach in and change the SD card in the Pi there. The Azteeg is closer to the motors and sensors in the rear. In configuration B, the Y cable carrier would exit toward the rear.
Now that I've taken time to describe all this, I'm envisioning Configuration C (no photo, sorry). Start with B, switch the Azteeg with the Pi so the Pi is closer to the front of the case, and rotate the Pi so its SD card slot is facing toward the laser bay for easy access. The Pi has many fewer connections, so it can be out of the way. The Azteeg's orientation is less obvious. It has power connections coming off both short ends of the board, gantry connections coming off both long ends, and connections to the front panel and rear chassis coming off everywhere. I might as well just orient it so its lettering is right side up. (-:
I've used the term "power distribution block" above a few places. I don't actually know what that should be. It will take in 110V power and redistribute it out to several other places. It's sort of a power strip. (-: I would also like it to have some outlets that are switched by a relay (or solid-state switch?) What do I need? Bart's BOM calls for a "DIN Rail" and several "DIN terminal blocks". Is that what I should use? Can I get a version of that that also has relays? (I hope that last question conveyed how very far I am from my areas of expertise here. (-: )
And while we're at it, what are some good ways to keep all these cables (and air hoses) tidy?
Thanks for all suggestions.
And here's Configuration B.
The two configurations have some things in common. The main power plug is always at the back right corner (not shown). The mains power distribution block, represented by a silver bow, is right in front of it. The PC power supply is along the side of the box. I will cut a hole in the skin to let its fan breathe. The water pump is not shown. It will be outside the chassis. The laser power supply is not shown. It will be on a shelf above all these bits, at the same height as the laser tube. So there are really three components to place.
The air pump has power and air in and out. The air outlet is the brass barb on the end. The air inlet is a black screw fitting sticking out the side of the opposite end. I powered on this air pump for the first time today. It sounds like a freakin' jackhammer. I want a quieter pump. But its connections are very simple.
- power from power distribution block
- air in from grommet at back
- air out to gantry
The Raspberry Pi is the front end processor. It will have these connections.
- power from PC supply, +5V standby
- Ethernet to back panel
- USB from type A connector to the Azteeg
- USB from type A connector to the front panel (optional)
The Azteeg X3 is the real time processor. It will also handle manual mode operations. It will have lots of connections.
- power from PC supply, +5V standby
- power from PC supply, +12V for motors and relays
- lead to PC supply to switch main power (+12V for motors and relays, +5V for LEDs)
- inputs from +Z and -Z limit switches in back
- inputs from -X and +Y limit switches on gantry
- outputs to Y and Z stepper motors in back
- output to X stepper motor on gantry
- input from door open switch in front
- input from E-Stop switch on top panel(?)
- inputs from buttons and joystick on top panel, details TBD
- outputs to LCD panel on top panel, details TBD (optional)
- SPI outputs to LED strip on gantry (optional)
- outputs to relays to switch power on air and water pumps and laser power supply (optional)
- inputs from thermistors in water lines (optional)
- input from flow meter in water line (optional)
So. Back to configurations A and B.
Configuration A puts the CPUs up front where they're near the control panels and the PC power supply's output, but they're far from the back panel and the sensors and motors in the back. In configuration A, the Y cable carrier would exit toward the front of the chassis.
Configuration B puts the CPUs closer to the rear. It is possible to reach in and change the SD card in the Pi there. The Azteeg is closer to the motors and sensors in the rear. In configuration B, the Y cable carrier would exit toward the rear.
Now that I've taken time to describe all this, I'm envisioning Configuration C (no photo, sorry). Start with B, switch the Azteeg with the Pi so the Pi is closer to the front of the case, and rotate the Pi so its SD card slot is facing toward the laser bay for easy access. The Pi has many fewer connections, so it can be out of the way. The Azteeg's orientation is less obvious. It has power connections coming off both short ends of the board, gantry connections coming off both long ends, and connections to the front panel and rear chassis coming off everywhere. I might as well just orient it so its lettering is right side up. (-:
I've used the term "power distribution block" above a few places. I don't actually know what that should be. It will take in 110V power and redistribute it out to several other places. It's sort of a power strip. (-: I would also like it to have some outlets that are switched by a relay (or solid-state switch?) What do I need? Bart's BOM calls for a "DIN Rail" and several "DIN terminal blocks". Is that what I should use? Can I get a version of that that also has relays? (I hope that last question conveyed how very far I am from my areas of expertise here. (-: )
And while we're at it, what are some good ways to keep all these cables (and air hoses) tidy?
Thanks for all suggestions.