Inputs and Outputs
This section describes using all inputs and outputs with default application loaded on the RAC18-IP device.
Universal Inputs
The RAC18-IP device has four universal inputs. In the default application, dedicated temperature sensors and/or potentiometer have to be connected to each input. The figure below presents the way all universal inputs are connected.
Universal inputs connection
Digital Inputs
The RAC18-IP device is equipped with four digital inputs. The way of connecting all signals to the inputs is presented in the figure below. Digital inputs I1 to I3 can be inverted, depending on the type of sensors connected to the device.
Digital inputs connection
Triac Outputs
The RAC18-IP device has two triac outputs to connect the actuators of heating and cooling valves. Both can work as typical binary outputs (for binary temperature control) or with the PWM. In the PWM mode, the output works in the period when two states are used (low state 0 V and high 230 V AC). The periods are defined by the PWM_Heating_Period network variable for the TO1 output and PWM_Cooling_Period network variable for the TO2 output (both are set to 300 seconds by default). The control signal defines the output of high state in working period (in percentage).
The way of connecting the actuators to the triac outputs in 4-pipe application is presented in the figures below.
Triac outputs connection
Digital Outputs
Fan Outputs
The RAC18-IP device is equipped with three relay outputs designed for connecting with the fan. The way of connecting the fan (depending on the number of speeds) is presented in the figure below. These outputs have internal connection to the power supply terminal and are protected by a built-in 6 A fuse. The total load for digital outputs O1, O3, O5, and triac cannot extend 6 A.
WARNING! Please note that the inductive load of the relays is limited to 75 VA.
Fan connections
Electrical Heater (O4)
The RAC18-IP device is equipped with a relay output for connecting the electrical heater. This output can be used for 1st or 2nd stage heating, depending on the S3 DIP switch configuration. This output is not internally connected to the power supply, therefore it is necessary to use external supply. Relay current cannot exceed 3 A for resistance load at 230 V AC power supply. The way of connecting the electric heater to O4 is presented in the figure below.
Note: The O4 relay voltage is always limited to 230 V AC, irrespectively of the controller's power supply.
Electrical heater connections
Electrical Cooler (O5)
The RAC18-IP device is equipped with a relay output for connecting the electrical cooler. This output can be used as 1st or 2nd stage cooling, depending on the S3 DIP switch configuration. The relay output is connected with the power supply internally, therefore it is not necessary to connect an external supply. The way of connecting the electric cooler to O5 is presented in the figure below.
Electrical cooler connection
Analog Outputs
The RAC18-IP device has 3 analog outputs 0-10 V DC, which can be used for controlling the following fan coil unit devices:
A1, analog heating valve actuator control;
A2, analog cooling valve actuator control;
A3, analog fan speed control.
The way of connecting all analog outputs is presented in the figures below.
Connection of analog valve actuators
Connection of analog fan control