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Installation Manual LOGS50 EN_MI_090221
1.11.4. EDGE SENSITIVE INPUTS
Digital inputs from 0 to 3 can be individually configured as inputs without
interruption or flank sensitive inputs. Inputs from 4 to 7 can only work as inputs
without interruption so they cannot be programmed as totalizers like the first
four inputs. When an input is configured as without interruption or triggered, the
logical value is stored in the corresponding variable automatically as it occurs
with no need of any reading task.
First four inputs can always be configured as flank sensitive inputs in the
configuration. Within this modality, they can be defined or as totalizer-frequency
meter or as trigger. In both cases, the user will define if the input must be
activated by means of ascending or descending flank.
A trigger input has the purpose of notifying an alarm, therefore, it is considered
that an input of this type spends most of the time in deactivated mode and from
time to time, an activation transition occurs. The object of this kind of input is to
trigger an event carrying out a task in connection with that event. On the other
hand, an input totalizer-frequency meter has the purpose of counting units or
pulses and frequency periodically. Regarding the thing last mentioned,
activation transitions are not allowed to trigger neither an event nor a task. It is
only allowed to define an event where the referenced variable be the aggregate
value or the frequency but never the digital value (‘0’ or ‘1’) from the totalizer-
frequency meter input.
When an input is configured as trigger, its behavior goes as follows:
That input is processed by means of an interruption. Its captured value will
not depend on a specific reading task; it will be a change in the state of the
input what will cause an immediate processing.
A filter for bounce suppression, consisting in the verification of Ton and Toff
times defined in the configuration table, will be applied automatically.
When an input is configured as totalizer-frequency meter besides these two
steps mentioned above, the system also carries out the following actions:
The functionality of the totalizer implies to keep a register with the total
accumulated value associated to that input. Every time activation occurs the
total or accumulated value will increase according to the configuration table
specification.
Besides the totalizer functionality, simultaneously, it is also activated the
period measurement which consists in measuring the existing time interval
between two transitions from the same input. These measured values that
correspond to the frequency measured
3
are also stored in several registers.
3 The value stored in the period measurement corresponds to the result of dividing the accumulated value of the associated
input by the elapsed time from the last input activation. This quotient it adjusted so that the measurement time interval coincides
with the one requested by user. (Example: a totalizer input has been assigned with an increment of 5m3 and it is having been
measured a period of 10s between activations which provide a flow rate of 0.5 m3/s. If the user stablishes that the period for the
calculus is 60s then, the stored value will be eq
3
Value assigned by the user in the LOGS50 configurator program. The system
time resolution is 5ms approximately, if the logger is in sleep mode, 20 ms are needed in order to proceed with the time
calculation; the maximum working frequency should not be overcome; while the time calculations are made, the logger remains
in active mode without turning to sleep mode.
