Heated bed wiring

Blacksheep99

I'm trying to fit a Maestro to an old St3Di modelsmart 280 printer. The heated bed (it's two heaters actually has the expected two power wires and the two for the thermistor. My question is without any diagrams am i safe to assume the blue and brown wires for the power to the bed are based on a UK standard and connect them as such? Thanks.

Veti

blue and brown sound like live wires.

measure the resistance between them.

Blacksheep99

@Veti said in Heated bed wiring:

blue and brown sound like live wires.

measure the resistance between them.

4.3 ohms I believe it reads

Veti

@Blacksheep99 said in Heated bed wiring:

St3Di modelsmart 280 printer.

at 24v that would be 134w, so yes you can wire that directly to the duet.

A Former User

@Blacksheep99 said in Heated bed wiring:

4.3 ohms I believe it reads

you might want to just short your multimeter probes togeter and see what they read when it should be 0 and correct.

Then you can use ohms law to work out the power at various voltages, but 4 ohms and 24v is only 144W .. however at mains voltage its probably waaay too much. how big is this thing?

Blacksheep99

@Veti said in Heated bed wiring:

@Blacksheep99 said in Heated bed wiring:

St3Di modelsmart 280 printer.

at 24v that would be 134w, so yes you can wire that directly to the duet.

Thanks. Silly question most likely but does it matter which is connected to terminals on the board?

Veti

unless there is a led. no

Blacksheep99

@bearer said in Heated bed wiring:

@Blacksheep99 said in Heated bed wiring:

4.3 ohms I believe it reads

you might want to just short your multimeter probes togeter and see what they read when it should be 0 and correct.

Then you can use ohms law to work out the power at various voltages, but 4 ohms and 24v is only 144W .. however at mains voltage its probably waaay too much. how big is this thing?

Thanks. I'll check this. The printer physically is large for the build size. Bed is 280x150.

Blacksheep99

@Veti said in Heated bed wiring:

unless there is a led. no

Thanks, I do appreciate the help. Slightly off topic, maybe I should start a build thread for my questions. The printer has a server controlled microswitch/probe for the bed levelling which also doubles as an end stop for X. How should I approach this with the Maestro?

My alternative idea was to use the door sensor microswitch as an end stop and use a different probe for the bed levelling sensor.

Veti

@Blacksheep99 said in Heated bed wiring:

server controlled

do you mean servo?

Blacksheep99

@Veti Sorry yes, should say servo

Veti

if you install version 3 of the firmware you can reconfigure the microswitch for x or probe, but it will take some work.

Blacksheep99

@Veti I've updated the board to 3.1 but then i have a whole new learning curve....

Veti

@Blacksheep99
sooner or later you will need to do it, as v2 does not get updates anymore

Blacksheep99

@Veti Already done it. I figure I should start on the latest stable version. I see 3.2 is likely released soon so I'll update to that once it is. I am familiar with gcode and the principles so I may as well learn the Duet side using v3

Veti

you cant assign 2 endstops to the same pin at the same time.

so what you will need to do is
when homing x configure the x endstop to use the pin and configure the z probe to the nil pin.
and when probing with the probe do the opposite.

this needs to happen in the homex, homez and homeall scripts.

Blacksheep99

Thanks, the logic makes sense. How i go about achieving it will be something to work out. My desire now is to get everything connected to the board and see if I can get some initial control.