Application Note: I3O2 Module & Float Sensors
The I3O2 module can be used along with float sensors to monitor and control water levels in a tank. With three inputs possible on the I3O2 module, three levels of a tank can be measured (such as high, medium, and low). For this note, the three input pins, IN1, IN2, and IN3, will be used for the float sensors placed at high, medium, and low water levels on a water tank. The relay output of the OUT1 pin will be used to trigger turning on and off the pump that is used to fill the water tank. The Wattmon and I3O2 module can be programmed to trigger the pump to turn on when the water level is below the bottom float sensor and turn off when the water level is above the top float sensor. This note will illustrate how this can be done.
The float sensors being used are similar to the one pictured in Figure 1. These can be purchased directly from the Wattmon site or through a third party. The float sensors will be placed at the designated levels in the water tank. When the water level goes below the float, there will be no pressure to keep the float head closed (like in the picture below), and this will send a signal to the I3O2 module which will be relayed to the main Wattmon. When the water level is above the float sensor, the float head will be closed. The one pictured below is upside down for the described situation.
Fig. 1: Float Sensor (http://www.tjskl.org.cn/images/czaedc30-pz276e57e-reduced_mini_reed_switch.html)
Set Up of I3O2 Module & Float Sensors
To set up the I3O2 module and float sensors, wire the black wire from the float sensor into the 5V pin of the I3O2 module. Wire the red wire into the IN1 pin. Do the same for the second and third float sensors; connect the first wire into the same 5V pin and the second wire into the corresponding input pin (IN2 or IN3). This may require some stripping of the outer black wire to expose the red and black wires. A schematic of the process can be seen below in Figure 2. The wires for each float sensor have been colored differently so that the diagram is easier to follow (float sensor 1 is red, float sensor 2 is blue, and float sensor 3 is green), but they will all typically be red.
Fig. 2: I3O2 & Float Sensors
The output relay of turning on and off the pump will be configured by using a contactor, a type of relay that will act as a switch, in conjunction with the I3O2 module. To set up the contactor with the I3O2 module, connect one thin gauge wire from either of the OUT1 pins on the I3O2 module to the L1 terminal on the input side of the contactor. Wire a second thin gauge wire from the other OUT1 pin to the A1 terminal on the contactor. Connect a thin gauge wire from the A2 terminal to the neutral (NO13 on the figure below) on the input side of the contactor. The pump can then be connected to the load side of the contactor (T1, T2, T3 terminals able to be used with three-phase). The contactor will switch on when there is a great enough voltage across the A1 and A2 terminals, allowing the power to flow through the contactor to supply the pump. The live wire will be the wire connected from L1 back to the I3O2 module. The neutral wire is the wire from A2 to the neutral contact (NO13) of the input side of the contactor.This can be seen below in Figure 3.
Fig. 3: I3O2 Module & Contactor
Configure Online Settings
Once the module is set up, you can go online to configure the settings and actions that the module will complete. If the I3O2 module has not been scanned yet, go to Control Panel > Devices > Add > Quick Scan Wired Bus for New Devices. The I3O2 module should then appear like in Figure 4 below.
Fig. 4: Device List
Once the module is scanned and appears in the device list, click on Action > Configure to assign specific roles to Input 1, Input 2, Input 3, and Output 1. There should already be roles that have been created that you can assign. In the Configure Roles section, choose Relay Output 1 for Output2, Digital Input 1 for Input 1, Digital Input 2 for Input 2, and Digital Input 3 for Input 3.
Next, to deisgnate when the pump will turns on and off, go to the Control Panel > Actions > Add Action (blue button located near the top right). The first action will turn on the pump. In the Action Trigger Condition(s) section specify the Value Type as Device Variable, Value 1 as Digital Input 1, Comparison as Is Equal To, Value 2 as Fixed Variable, and Value 2 Type as 0. Add a second action trigger condition specifying the Value Type as Device Variable, Value 1 as Digital Input 2, Comparison as Is Equal To, Value 2 as Fixed Variable, and Value 2 Type as 0. In the Actions to Execute section, specify the Action as Switch On and the Variable as Relay Output 1. This is saying that the pump will be turned on whenever the Digital Inputs 1 and 2 are equal to 0. A screenshot of this process can be seen below in Figure 4.
Fig. 4: Configure Action - Fill Tank
The second action will be to turn off the pump. In the Action Trigger Condition(s) section specify the Value Type as Device Variable, Value 1 as Digital Input 3, Comparison as Is Equal To, Value 2 as Fixed Variable, and Value 2 Type as 1. In the Actions to Execute section, specify the Action as Switch Off and the Variable as Relay Output. This is saying that the pump will be turned off when the digital input 3 from the high float sensor is equal to 1 or is closed. A screenshot of these details can be seen below in Figure 5.
Fig. 5: Configure Action - Turn Off Pump