Technical information

7878
Functions.(continued)
Functional characteristics
Congurable functions Number
1 of the 6 congurable functions (using the Advantys conguration software)
Frequency meter
This basic function measures the frequency received on the IN A input.
This frequency is always expressed in hertz (number of pulses per second), with a precision
of 1 Hz.
Also measures the speed in units per second. The number of points to be received on the IN A
input, corresponding to one unit, must be dened from 1 to 255.
The maximum frequency on the IN A input is 40 kHz in both cases (without ltering).
Response time: < 0.2 s (frequency 2/40 kHz), < 1 s (frequency 0.2 kHz)
Event counting
This function provides the value of the number of pulses received on the IN A input during a unit
of time. The unit of time is congurable: 0.1s, 1s, 10 s or 1 minute.
The IN B input can be used to reset the internal time base which provides the time unit.
The maximum number of pulses counted during a unit of time is 65,535.
The minimum pulse duration on the IN A input is 10 µs (without ltering).
Response time: < 0.5 ms
Period measurement
Measures the elapsed time during an event or between two events (on IN A input) according
to the selectable time base of 10 µs, 100 µs or 1 ms. The maximum event duration is 0.655 s,
6.55 s, or 65.5 s, respectively. The maximum frequency on the IN A input is 200 Hz.
Response time: < 0.5 ms
Downcounting
The IN B input starts or restarts the counter by resetting it to the setpoint value dened by the
high threshold value.
When the counter is running, any pulse received on the IN A input decreases the counter.
The counter stops when it reaches 0.
The maximum setpoint value is 65,535.
The maximum frequency on the IN A input is 40 kHz (without ltering).
Response time: < 0.5 ms
Loop (modulo) counting
The IN B input starts or restarts the counter by resetting it to 0. The IN B input also captures
the previous counting value before the reset to 0.
When the counter is running, any pulse received on the IN A input increases the counter.
The counter automatically returns to zero when the number of pulses received equals the
modulo dened by the high threshold value.
The maximum modulo value is 65,535.
The maximum frequency on the IN A input is 40 kHz (without ltering).
Response time: < 0.5 ms
Up/down counting
The RST input starts or restarts the counter by resetting it to the preset value.
When the counter is running, counting increases or decreases according to the pulses received
on the IN A and IN B inputs (by default, IN A increases the counter and IN B decreases the
counter).
By conguration:
 Input IN B can dene the counting direction of the pulses received on IN A.
 Inputs IN A and IN B can receive signals from an incremental encoder.
The counter value is limited to a low limit of 0 and a high limit of 65,535.
Response time: < 5 ms
OUT1 and OUT2 output functions
Depending on requirements, each of the counter module’s two outputs can be congured for
one of the following operating modes:
 No direct action.
 The output is activated when the counter value is less than the low threshold.
 The output is activated when the counter value is between the low threshold and the high
threshold.
 The output is activated when the counter value is greater than the high threshold.
 A pulse is generated on the output when the counter passes the low threshold (downcounting).
 A pulse is generated on the output when the counter passes the low threshold (upcounting).
 A pulse is generated on the output when the counter passes the high threshold
(downcounting).
 A pulse is generated on the output when the counter passes the high threshold (upcounting).
 The output is activated when the counter is started (RUN). This option is only available for
the downcounter function.
 The output is activated when the counter is stopped (STOP).
 The output is activated when the captured value is less than the low threshold. This option is
only available for the modulo function.
 The output is activated when the captured value is between the low threshold and the high
threshold. This option is only available for the modulo function.
Modicon STB distributed I/O
solution
STBEHC3020KC counter module