Digital outputs
Edge
Note:
Specific inputs and outputs are present only on certain models of Unipi Edge. Overview of available I/O for each model can be found here.
Each digital output (solid state MOSFET relay) is wired to its own DOx connector. To switch inductive loads, it is necessary to connected adequate protection, e.g. snubber, otherwise there is a risk of possible damage to the device's digital outputs. Both terminals can be wired with both positive and negative polarity. Switching of each output is indicated by LED with the label and number corresponding to the output.
Note:
Digital outputs do not possess their own power source (meaning they are dry contacts) and serve only to switch A and B terminals together where the load can be connected. This means that if 28 V are supplied to one of the terminals and the digital output is on, then same voltage would appear on the other terminal.
Note:
Digital outputs can be configured to PWM mode (pulse width modulation) using a suitable SW (Mervis, EVOK or by directly editing the Modbus registers).
Connection
The following pictures describe the basic connection of digital output:
Attention:
To switch some loads it is necessary to add adequate protection elements, e.g. snubber!
SINK
SOURCE
Special functions
Aside from the standard inputs and outputs, Unipi Edge units also feature additional functions for broadening the possible applications, performance optimization and monitoring of the entire project. These functions are calculated directly by the I/O microprocessor, making them independent on the control software.
Here you can find more information and tutorials about special functions for:
PWM
PWM abbreviation stands for Pulse Width Modulation. This function serves for generating a rectangular signal of a given frequency and duty cycle on digital output and is used for digital transmission of an analog signal (such as 0-100%). PWM is typically used to regulate components powered by direct current in a way not possible with analog regulation. For example, the function can serve as an effective regulation of heating cartridges and LED lighting through an SSR relay.
Direct Switch
The DirectSwitch function can be used on any Unipi Edge unit equipped with both digital inputs and digital outputs.
This function allows logical connection of digital input to digital output output to automatically perform one of the available operation. DirectSwitch is independent on the control software running on unit and is suitable for control of lighting or any other time-critical applications (typically, the output response time matches the input response).
The function can be configured for one of three modes:
- Copy - input state is copied to the output
- Inverse copy - negated state of the input is set on the output
- Switch - if a rising edge is detected on the input, the output state is negated
- (Block - disables DirectSwitch)
Please note:
DirectSwitch function can be configured only between digital input and digital output with matching number, ie. only DI1 can be connected only to DO1. Some digital inputs might not have corresponding digital output, in which case DirectSwitch functions is not available for that input.
Attention:
If DirectSwitch is applied to an output, it is not possible to write onto output (DO) in a regular way. Instead, you need to set the ForceOutput register to TRUE for approx. 1 second.
Default configuration
This function is used to save the current configuration of inputs, outputs and other interfaces into memory. In case of power cycle of the device or reboot, the stored configuration is loaded and applied. This functionality is also known as “copy
running-config to startup-config”.
| Stored data | Default configuration | Default (calculated) values |
|---|---|---|
| Output value | FALSE | |
| PWM configuration | off duty cycle: 0 resolution: 100 | frequency: 100 Hz step: 1% |
Master Watchdog
This function runs on the I/O board microprocessor and continuously monitor the commands from the application running on the unit. If no commands are detected within a configured time (MWD Timeout), the I/O board's processor automatically reboots and reverts to the default configuration described above. This function ensures a safe configuration is set in case of emergency situations (unit failure, communication error or software issues) to prevent damage to controlled devices or any hazards to personnel.
Technical parameters
| Output terminals | DOx |
|---|---|
| Output connections | A, B |
| Output type | Solid state MOSFET relay |
| Output load type | Resistive load (specific values are listed below) |
| Maximum switching voltage | 48 V ⎓ |
| Switching current continuous (up to 25°C) | 500 mA |
| Rate of current reduction (above 25°C) | 5 mA for each 1 °C |
| Switching current pulse | 1.5 A |
| Highest short-circuit current | 6 A |
| Total rated load | 48 V⎓, 500 mA |
| Inductive load protection | No, external snubber needed |
| Maximum switching speed | 500 Hz / 8 bit |
| Functions of output | PWM |
| PWM Maximum frequency (recommended) | 200 Hz |
| PWM Maximum resolution | 16 bits |
| Galvanic isolation | Yes, see illustration below (Functional, cannot exceed SELV) |
Internal isolation of DOs
