Canbus SB2240: Omron TL-Q5MC2-Z is a BAT85 diode needed?

[Jqw767]

Printer Model

Voron 2.4 350

Extruder Type

Clockwork 2

Cooling Type

Stealthburner

Sticking with the Omron TL-Q5MC2-Z from my formbot kit (I have backup Omrons…) in my Canbus BTT SB2240 build for now. Wondering two things:

1) option of 12 or 24V… as Omron runs from 10-30V I would go with 24V to be closer in the „middle“… or any benefit of 12V here?
2) connecting the Omron probe to the Octopus required a BAT85 diode… do I need this on the signal wire between Probe and SB2240 board?

 

[Sandman50]

The omron is specced to work between 10 and 30 VDC, so 12 VDC is fine, but you have the option for 24 VDC with the EBB.

The analog connections to the Octopus assume that it uses a multi-wire harness. The diode is to prevent cross talk between the supply and signal voltages. So the CAN head won't need that as the signal is already isolated by the IC.

Page 15 of the BTT manual says to just connect it directly to the board:

EBB/EBB SB2240_2209 CAN/Build Guide/EBB SB2240 2209 CAN v1.0 Build Guide.pdf at master · bigtreetech/EBB

Contribute to bigtreetech/EBB development by creating an account on GitHub.

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It's NPN so you need the little jumper above the voltage selection.

 

[Jqw767]

The omron is specced to work between 10 and 30 VDC, so 12 VDC is fine, but you have the option for 24 VDC with the EBB.

The analog connections to the Octopus assume that it uses a multi-wire harness. The diode is to prevent cross talk between the supply and signal voltages. So the CAN head won't need that as the signal is already isolated by the IC.

Page 15 of the BTT manual says to just connect it directly to the board:

EBB/EBB SB2240_2209 CAN/Build Guide/EBB SB2240 2209 CAN v1.0 Build Guide.pdf at master · bigtreetech/EBB

Contribute to bigtreetech/EBB development by creating an account on GitHub.

github.com

It's NPN so you need the little jumper above the voltage selection.

Great, thanks. I saw that the manual shows the outline of the Omron proximity switch, but as it‘s not explicitly described I wanted to go the safe route.

 

[scharkalvin]

The Omron signal output will show a logic 1 level near its power supply level, and a logic 0 level near ground. If the input line at the micro controller can't handle 12-24 volts (probably not!) then the diode is used, with the cathode connected to the Omron and the anode to the MC. The signal input at the MC should have an internal or external pullup to VCC (3.3v or 5v depending on the processor used). When the Omron outputs logic level 1, the MC input will just see its pullup voltage level, when the Omron is at logic 0, the MC will see logic level 0 (gnd). The diode must be a Schottky diode (a germanium diode might work here if it has a reverse voltage ratting of at least 40V), to meet the logic 0 level voltage requirement of the MC. If you already have a level translator installed at the MC input then the diode is not needed. One can also use a MOSFET (2N7000) or an opto-isolator for this function.