Rambo 1.1B 2 heated beds and 1 extruder? December 05, 2014 01:34AM |
Registered: 11 years ago Posts: 9 |
Re: Rambo 1.1B 2 heated beds and 1 extruder? December 05, 2014 08:51AM |
Registered: 11 years ago Posts: 869 |
Re: Rambo 1.1B 2 heated beds and 1 extruder? December 07, 2014 06:45AM |
Registered: 10 years ago Posts: 590 |
Re: Rambo 1.1B 2 heated beds and 1 extruder? December 08, 2014 08:18AM |
Registered: 11 years ago Posts: 869 |
Maybe after a while you wouldn't notice it, but I still think every 15 seconds hearing a click would get annoying. I guess it would also depend on how loud it is over normal (and unavoidable) sounds the printer makes such as steppers and fans.Quote
enif
If you go with the cheap 40A mechanical automotive relay (as I do), you can change the BED_CHECK_INTERVAL from the default 5000 to 15000. This reduces the clicking sound mentioned by cdru to max. once every 15 seconds, so it's no longer an issue (at least for me). But the temperature of the heated bed will still be kept to within a few degrees from the target value. In Marlin the BED_CHECK_INTERVAL is in Configuration_adv.h, in Sprinter it's in Configuration.h.
Re: Rambo 1.1B 2 heated beds and 1 extruder? December 13, 2014 03:45AM |
Registered: 11 years ago Posts: 9 |
Quote
RepRap Electro
From an electronic point, it is possible, the mosfets that are used for the heat-bed and for the heat-0, fan-0 and heat-1 connectors are the same, however they are using different power rails. The heated bed uses a separate power rail which is protected by a 15A fuse while the heaters use a different power rail protected by a 5A fuse.
The fuse for the heaters can be replaced with a similar fuse with higher current rating but it will be sharing the current with the hotends and fans.
The fuse is a Nano2 fuse and Littelfuse has one rated for 15A with part number 0448005.MR (http://www.littelfuse.com/products/fuses/surface-mount-fuses/nano-2-fuses/448/448015.aspx).
The RAMPS for example uses a fuse of 11A for the heat-bed and a 5A fuse for the heaters and motors, so I think 15A should be able to handle both the additional heat-bed and the hotends, you may want to check the current requirements of your heated beds.
An alternative solution could be to replace the 15A ATO fuse for the heat-bed and wire both heat-beds to the same connector on the RAMBo, the mosfet itself should be able to handle up to 60A.
You will however have issues if the heat beds don't reach the same temperature at the same time, as you won't be able to control both separately. The connectors themselves might also not be suited for such a high current, so I'd be worried that the connectors might melt.
In either case though, know that these are not tested configurations and while they should work, there are no guarantees that they will.