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Digital inputs
Special functions
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 64-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 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)
Note:
DirectSwitch function can be configured only for the corresponding input and output, ie. only for DI_y.x input and DO_y.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. DI_x.y and DO_v.z. It is also not possible to use the function for a single input and multiple outputs at the same time.
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.
Technical parameters
Input type | SINK |
Input terminal | DI |
Common ground | DIGND |
Maximum voltage for FALSE | 3 V DC |
Minimum voltage for TRUE | 7 V DC |
Maximum voltage | 35 V DC |
Non-defined state | 3-7 V DC |
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 |
Galvanic isolation | Yes (between the groups*) |
Insulation voltage | 2 000 V |