Eaton XN300 - Page 137

20 XN-322-16DIO-PC05 digital input/output module
20.3 Wiring
133 XN300 slice modules 02/24 MN050002EN Eaton.com
20.3.2 Counter functions for inputs 1…4
Internal module counter registers are connected internally to digital inputs 1
to 4. These counter registers make it possible to count signal pulses at the
inputs.
The PLC program must manage any register overflows at the counter
registers (the program's cycle times and maximum counter frequency must
be taken into account).
The following counter functions can be configured:
• Counter mode (simple counting): The 8-bit counter register for an input
will be incremented every time there is a rising signal pulse at that input.
Objects 0x3172 to 0x3175 are the corresponding 8-bit counter registers.
• Incremental encoder mode: Counts by interpreting the signals from two
inputs using X4 encoding and incrementing a 16-bit counter register.
Objects 0x3176 to 0x3177 are the corresponding 16-bit counter
registers.
• PWM time measuring mode: This mode supports time measurements
at inputs 1 to 4.
The "high time" for an input will be the time that passes between the
rising and falling edges of a signal at that input. When a rising signal
edge is detected, a counter will start being incremented every s. Then,
when the corresponding falling signal edge is detected, the counter
value will be recorded in the corresponding 16 bit PwmHighTime(x)
count register. Once the value is transferred to PwmHighTime(x), the
counter will be reset. "High times" will be recorded in objects 0x3178,
0x317A, 0x317C, 0x317E.
Period t
p
will be the time that passes between the rising edges of the
signal at the digital input. When the first rising signal edge is detected, a
counter will start being incremented every s. Then, when the second
rising signal edge is detected, the counter value will be recorded in the
corresponding 16 bit PwmPeriodTime(x) counter register. Once the
value is transferred to PwmPeriodTime(x), the counter will be reset.
"Period times" will be recorded in objects 0x3179, 0x317B, 0x317D,
0x317F.
Figure 81: PWM signal measurement
a High Time
b Low Time
t
① ② ②①
t
P
t
P