Using Multiple Bed Heaters

justine.haupt

Here's a summary of what I did to get multiple bed heaters working, thanks to a lot of hand-holding:

1. 4 bed heaters, connected to the default bed heater as well as the E4, E5, and E6 heaters on the Duex5.
2. The bed heaters are configured in config.g as follows:

[[language]]
; ###Configure Bed Heaters###
M140 P0 H0		;Tie the E4 (H5) heater and thermistor to P0 as a bed heater. This is so by default but included for visual consistecy in this file.
M140 P1 H5		;Tie the E4 (H5) heater and thermistor to P5 as a bed heater. 
M140 P2 H6		;Tie the E5 (H6) heater and thermistor to P6 as a bed heater. 
M140 P3 H7		;Tie the E6 (H7) heater and thermistor to P7 as a bed heater. 

M305 P0 R4700 T100000 B3950       ;Set thermistor parameters
M305 P5 R4700 T100000 B3950   
M305 P6 R4700 T100000 B3950   
M305 P7 R4700 T100000 B3950   

M307 H0 A90.0 C700.0 D10.0 B1		;Set heater model settings
M307 H5 A90.0 C700.0 D10.0 B1
M307 H6 A90.0 C700.0 D10.0 B1
M307 H7 A90.0 C700.0 D10.0 B1

M143 H0 S120 ; Set maximum heater temperature.
M143 H5 S120 ;
M143 H6 S120 ;
M143 H7 S120 ; 

M570 H0 S1200 ; Set maximum heating time (Snnn, in seconds).
M570 H5 S1200 ; 
M570 H6 S1200 ; 
M570 H7 S1200 ;

3. If I want to turn all the bed heaters on and set them to nn*C, I send:

[[language]]
M140 P0 Snn
M140 P1 Snn
M140 P2 Snn
M140 P3 Snn	
M116		;wait for all heaters to stabilize

Notes:

-M140 P0 Snn is the default heater output, so if a heated bed is specified in the slicer settings this will be redundant.
-If adding this to the start script in Simplify3D, it seems better to remove the normal bed heater from the Temperature Tab altogether. Otherwise, the start script doesn't run until after the first heater zone has come up to temperature and stabilized, which means a single heater needs to fight against the thermal mass of the whole build plate before the other heaters are ever woken up, so it may not get up to temperature at all. It's still not great because the extruder will have come up to temperature and be sitting like that the whole time the bed is coming up to temperature. But unchecking "wait for temperature controller to come up to temperature before beginning build" for the extruder helps so at least everything comes on at the same time.
-Hopefully Simplify3D will soon support multiple bed heaters. Someone on the Simplify forum claims it already does (https://forum.simplify3d.com/viewtopic.php?f=23&t=6976), but I don't know what they're talking about. I posted on that forum to address the question.