Digital inputs
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.
Digital inputs serve for an indication of TRUE/FALSE logic states and can be also used as counters to collect data from pulse meters, monitor engine revolutions etc. Another possible application is to connect input and output using the DirectSwitch function.
Note:
TRUE logic state (switched on) on input is indicated by LED with the corresponding marking matching the input label.
Connection
Each digital input is paired with a separate COM terminal, but all COM terminals are internally connected. The negative pole of the DC voltage source connects to the COM terminal and the positive pole of the source connects via an external device to the DIx terminal. See the following image for illustration:
Note:
For connection of external devices to digital inputs, we recommend using a different (separate) power supply from the one used to power the device (unit/Extension) in order to ensure galvanic isolation.
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:
Debounce
Function Debounce serves for filtration of undesirable oscillation on inputs. When no unit is given, then its value is represented in hundreds of μs (i.e. value 10 equals 1 ms). Impulse (rising edge) is processed as valid only in case it equals logical 1 for the whole set duration.
Counter input
One of the most interesting functions is counter input - a high-speed rising edge counter independent on the control software. Simply put, the counter can very accurately detect even very short pulses.
Counter inputs are suitable especially for collecting data from energy meters, water meters, gas meters and other pulse meters installed in HVAC systems. They are also useful for reading engine revolutions. For this purpose, Unipi units feature 32-bit registers. When the maximum value of the counter (4 294 967 295) is exceeded, the counter resets to 0. Counter inputs can be used at up to 10 kHz frequency; in the Mervis IDE library devices, they are labelled as CNT inputs.
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 |
|---|---|
| Debounce | 5ms |
| DirectSwitch | off (block) |
| Counter | 0 |
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
| Input terminals | DIx |
| Common ground | COM |
| Input type | SINK |
| Voltage for FALSE | -3 … 5 V ⎓ |
| Voltage for TRUE | 9 … 35 V ⎓ |
| Indeterminate state | 5 … 9 V ⎓ |
| Maximum voltage | 35 V ⎓ |
| Input resistance for TRUE | 6 200 Ω |
| Voltage drop on DI diode | 1.2 V |
| Minimum pulse length | 20 μs |
| FALSE –> TRUE delay | 20 μs |
| TRUE –> FALSE delay | 60 μs |
| Maximum CNT counter input frequency | 10 kHz |
| Input functions | Counter (including memory), Direct Switch |
| Galvanic isolation | Yes, see illustration below (Functional, cannot exceed SELV) |
Internal isolation of DIs
