D105: TDS sensor connection

TDS level sensor

You can connect a TDS sensor to the universal meter smart-MAC D105, which serves to determine the hardness of water and measures the concentration of salts dissolved in water.

TDS is the total dissolved solids.

A TDS sensor for connecting to 1/8 '' fittings is supplied with an interface board that converts the signal on the sensor to an analog voltage.

Wiring diagram:

• connect the black wire of the sensor to terminal 1: GND (Ground or -5V)
• connect the red wire of the sensor to terminal 6: + 5V
• yellow/green sensor wire connects to terminal 5: ADC

TDS sensor wiring diagram for smart-MAC D105

Dashboard widget settings

Add a widget indicator, chart or table to the board.

Select your smart-MAC D105 device.

It is recommended to combine TDS liquid level measurement with temperature measurement and use a correction temperature coefficient.
In the section "Arithmetic operation" select the function f(x) and write the function for calculating TDS in [mg / l]

var vc = d.ADC / (1.0+0.02*(d.T1-25.0));  
(133.42*vc*vc*vc-255.86*vc*vc+857.39*vc)*0.5;

where: 

d.T1 is the temperature of the liquid measured by the temperature sensor T1.

Change d.T1 to the temperature T1-T5 with your connection. If the temperature sensor did not connect, then instead of d.T1, use the closest data to the temperature of the liquid.

Set up notifications on the device and control the built-in relay.

To configure notifications on the D105 device and automatically control the built-in relay according to the TDS level, you should define a simplified formula for calculating the voltage at the analog input with the corresponding TDS level.

Vout = TDS * 0,0023

Where:
TDS - the level at which the alert should come or the relay is activated;
Vout - voltage at the analog input, with the corresponding TDS.

Mounting options

The TDS sensor is designed for installation on OSMOS fittings.
These are plastic crimp tees, as in the photo.

To mount the sensor on a DN20 pipe (for example) you will need 2 fittings:

1. Tee DN20 - G1/4'' - DN20 (as for a standard pressure gauge)
   
2. Straight fitting for OSMOS to G1/4"

Done!