DigOutUser - relay control switch based on temperature or vehicle speed

[ArT]

I would like to show you new feature in UTCOMP-PRO v3.4 (update coming soon)

As you can see, in UTCOMP-PRO currently digital output on pin B7 (DigOutUser) is not used- it will change soon Since v.3.4 there is possibility to control digital output switch based on selected signal source. As signal source you can choose any temperature or vehicle speed. Digital output state may be switched between two states: +5V and Hi-Z (disconnected). Recommended load is <50mA (maximum 100mA), so in most cases it will be used to control monostable relay switch with 5V coil.

UTCOMP-PRO_Controller.jpg (46.08 KiB) Viewed 30657 times

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DigOutUser specification (pin B7 in UTCOMP-PRO):

• +5V in ON mode
• HiZ (disconnected) in OFF mode
• current load <50mA (max 100mA*)

*PLEASE NOTE! exceed >100mA on output load can make UTCOMP unstable (e.g. switching off when to much load is connected, wrong voltage readings on analog inputs etc.) or even make it failure to work (e.g. burning internal fuse for power supply)

UTCOMP-PRO_DigOutUser_Relay-Switch_Control_1.jpg (68.69 KiB) Viewed 30657 times

Input signal source:

• temperature inside the vehicle
• outside temperature
• engine or cooling temperature
• oil temperature (e.g. for engine or gearbox)
• user temperature
• vehicle speed

UTCOMP-PRO_DigOutUser_Relay-Switch_Control_3.jpg (43.19 KiB) Viewed 30657 times

Regulation modes:

• above upper (HI) threshold
• below lower (LO) threshold
• above LO and below HI thresholds
• below LO and above HI thresholds
• manual mode
  

UTCOMP-PRO_DigOutUser_Relay-Switch_Control_2.jpg (40 KiB) Viewed 30657 times

Additional regulation conditions:

• possibility to set hysteresis
• possibility to set minimum battery voltage for regulation (ability to disable regulation when battery voltage drops below selected value, e.g. regulation is enabled only when engine is running)

Examples:

• relay control switch based on internal temperature (e.g. for air condition control - climatronic)
• relay control switch based on engine/cooling temperature (e.g. for cooler control, glow plugs control etc.)
• enabling buzzer or LED for selected vehicle speed (e.g. speed limit warning)
• relay control switch based on vehicle speed (e.g. door auto-lock mechanism)

Is relay always required?
If current load on output is above 100mA (0,1A) or there is need to control external device with different voltage levels (e.g. 12V) than monostable relay is required. You will not need relay if you want to control low power devices, e.g. buzzer or small LED.

Relay selection guide:

• monostable relay with 5V coil
• recommended coil resistance above 100 ohms
• relay switching power below 250mW (<0,25W)
• example relays: AZ850-5

[JasonD]

Hi Art, in the future do you plan to add more signal sources? I was hoping to see engine RPM so this feature could be used for a shift light.

[ArT]

DigOutUser is low freqency output (1 time per second, output delay may be up to 200ms) and it's to slow for reacting on RPM signal or shiftlight

[rlinares40]

would this be able to trigger a relay for a small fan with a 3-5 amp max draw?

[ArT]

would this be able to trigger a relay for a small fan with a 3-5 amp max draw?

3-5 amp is current for fan, for relay coil it will be probably 50mA which is 100% fine. You need to use relay with 5V coil.

[rlinares40]

would this be able to trigger a relay for a small fan with a 3-5 amp max draw?

3-5 amp is current for fan, for relay coil it will be probably 50mA which is 100% fine. You need to use relay with 5V coil.

would a 6V relay work? it still should provide enough voltage to switch it on at 70-75%

https://temcoindustrial.com/6v-30-40-am ... utomotive/

Cannot find any 5V automotive relays.

[rlinares40]

would this be able to trigger a relay for a small fan with a 3-5 amp max draw?

3-5 amp is current for fan, for relay coil it will be probably 50mA which is 100% fine. You need to use relay with 5V coil.

would a 6V relay work? it still should provide enough voltage to switch it on at 70-75%

https://temcoindustrial.com/6v-30-40-am ... utomotive/

Cannot find any 5V automotive relays.

Or maybe a IRLZ44NPBF MOSFET? The 5V signal wire would go to the Gate, the fan to the Drain, and the ground to Source.

https://www.digikey.com/en/products/det ... PBF/811808

[rlinares40]

Or maybe the example attached? One of the 3 options should work?
ignore where the picture says 24VDC, they sell a 5VDC option.

5V Relay Example.jpg (81.24 KiB) Viewed 31 times

[ArT]

the last option should work fine, I do not have manual for it but it may be required to connect +5V or +12V to DC+ and DigOutUser only to IN input

relay with nominal 5 VDC coil (AZ850-5 variant):
https://www.azettler.com/pdfs/az850.pdf

option with mosfet will also work (as +12V switch controlled with +5V output) but it requires some additional elements. Above board will be better and safer solution.