I’m wondering if I can get some help on wiring a heat bed with an external temp control. The machine I have is a ZeePro Zim, and everything I’ve researched says it’s kind of a pain to do a third party heated bed. Since the company is now defunct, I can’t get an official heated bed. Anyway, my thought is to use a temperature controlled relay to turn heat the bed. My other idea was to wire a secondary relay into my heatsink fan since it kicks on automatically when the hot end gets to 60c. That way as my hotend heats up and the fan kicks on, the bed kicks on, and when the fan turns off the bed turns off. I’m having a difficult time figuring out just how to integrate that secondary relay. Could I get someone to look at this mockup to see if I’m on the right track?
Only problem is where is the positive wire going to the fan?, it would be best to wire the fan to run off the same positive and negative of the hot bed. That way you save money right off the bat because you then won’t need the second relay. Also i don’t think that relay can run off of the fan connector.
@NavyMustard Is there something I can use that essentially senses when the fan is powered on? I want it to sense that and then have it turn on the power to the temp controller. I’m thinking on that side of things I’d want to wire it to the ground and normally open?
I would use a PID box with SSR. That temperature controller you show is a thermostat type which will cycle the heat on and off around the set temperature. While you can set it narrowly, you’re probably going to swing at least a degree while PID can get you within a tenth of a degree. If your bed “heaves” due to temperature, you will get some Z banding because of the wider temperature swing.
@Jeff_DeMaagd Something like this? Inkbird Dual Digital PID Temperature Controller 2 Omron Relay Thermostat 110-240V ITC-100VH + 40A SSR + K Sensor https://www.amazon.com/dp/B00ADHNSGI/https://www.amazon.com/dp/B00ADHNSGI/ref=cm_sw_r_cp_api_2csOybFDCAN4Q
Yes. That kit should have what you need.
@Jeff_DeMaagd Thanks. Any thoughts on the best way to integrate that second relay so that my temp unit is powered on when the fan kicks on?
So to set it up to “sense” the fan you would need to set the firmware to where it is always on or always off (to trigger relay), and have the fan and the relay hooked up to the positive and negative pins on the fan connector that way the fan turning on would also trigger the first relay to allow power from the positive rail of the power supply to flow to the second relay (the relay the thermostat controls) and then from the relay to positive of the bed and connect the negative of the bed strait to your power supply.
But be careful as I do not know how much power the fan connector will allow. As in frying the mosfet that controls the fan.
I would think you could just use a Double Pole Single Throw Relay (DPST)! You’d just have to find a relay that fits the coil voltage specs and the voltage & current rating of your hot bed!..and depending on the wattage of your hotbed, if it uses A/C line voltage, you might be able to use this to control your amount of heat!..I believe it works with up to 600 watts!:
http://www.inlandhobby.com/Soldering_Iron_Controller_p/60014.htm
@K1111 Do you have any access to the firmware? Marlin has autofan for when a sensor exceeds a set temperature.
Check out the community forum. There are many that have added heated beds using the built in connector to control it with separate power and a relay (including myself). http://zeeproforums.technobly.com/t/create-your-own-heated-printbed/132/5
@Joe_Fochs I have misread this earlier, but I was under the assumption that you have to use special four and six pin connectors to connect to the existing board.
@Jeff_DeMaagd I’ll have to find out. This uses a custom board, so I’ve never messed with it at that level.
@Mindless That board is really interesting. Thank you!
@K1111 The 6 pin connector is the same as a computer pcie power connector (like for a GPU). I simply cut up some old power supply wiring I had. I would suspect that you could find some wiring online for fairly cheap if you don’t have one lying around. For the power connection you can either pay a bit more for a power supply with the same connector as the one that came with the Zim, or you could replace the connector on the board with something more standard as others have done. For simplicity I purchased a power supply with the 4 pin din connector and spliced in to run power to the relay.
@Joe_Fochs Do I even need the 4 pin din? From the schematics I see on that post, couldn’t I just use a 6 pin connecter with just the thermistor/relay, then power the bed separately using my switching power supply? Pretty much the same way this d-bot has the bed wired? https://cdn.thingiverse.com/assets/15/31/5e/8b/3c/D-Bot_Electrical_Diagram.pdf
@K1111 Well the way the Zim modification works is to “intercept” the output voltage that the Zim would send to the heated bed and use that to drive the relay. The reasoning as I understand this is that the 6 pin molex connector is not really rated for the amperage that would be put through it by a heated bed. That’s the only reason people are using a separate relay. So in this case you still need to power the heated bed connection. Thinking about it now I suppose it would be possible to jumper the main power to the heated bed connector internally just to run the signal and then power your relay via some other power supply. Otherwise it would also be feasible to simply power the 4 pin din connection with a separate power supply and run the 6 pin molex connections straight to the heated bed. I opted for the “safer” route to eliminate the possibility of a melted connector or possible fire.
@Joe_Fochs
…I did the same kind of set-up for a horn I installed on my vehicle! …I used the power from the horn button in the car to trigger a relay which closed a loop that was connected to the higher amperage new horn pair and fused it directly to a battery! Works Well! In this instance of a hot bed, I would add the extra control of the heat/temperature/current control in the post that I made above with what is called the “mini phaser”–works up to 600 watts with regular AC line voltage.
@Fook_INGSOC Yea that’s pretty much how it’s done. For the Zim, it already has thermistor control, it’s just a matter of wiring the thermistor from the heated bed into the 6 pin molex connector. Then it can be controlled by the ramps board inside. The software side is pretty easy using octoprint. I’m not sure how other software might handle it.