Advanced functions of Inputs and Outputs

The following article contains the basic info about advanced functions of inputs and outputs For detailed info and technical parameters of advanced functions, please visit the following subcategories:

You can find default values of these functions for each device in Default configuration section in input and output articles.

Master Watchdog
This function runs on the section's (extension module's) 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 section's (extension module'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.

More detailed info about Master Watchdog is available on this link.

Direct Switch

The DirectSwitch function can be used on any unit or extension module equipped with digital inputs and digital or relay outputs within a single section.

This function allows logical connection of digital input to digital output or relay 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)

(i)

Please note:
DirectSwitch function can be configured only for the corresponding input and output, ie. only for DIy.x input and DOy.x (ROy.x) output, where x and y (if the y is given) numbers must match. It is not possible to use DirectSwitch simultaneously for input and output with mismatched labels, eg. DIx.y and DOv.z. It is also not possible to use the function for a single input and multiple outputs at the same time.

(i)

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.

More detailed info about Direct Switch is available on this link.

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.

More detailed info about Debounce is available on this link.

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.

More detailed info about input Counter is available on this link.

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.

More detailed info about Pulse-width modulation is available on this link.