To reset/overwrite the pulse counter, use function IO_PULSEIN_RESET.
Epec 3724 control unit contains 8 pulse input channels.
|
To reset/overwrite the pulse counter, use function IO_PULSEIN_RESET. |
The table below lists all software channels and related output pins.
Possible software channels and pairs (draft)
Pin |
Min frequency for frequency and pulse width measurement |
Max frequency |
PI Channel |
X3.16 |
0,1 Hz |
20 kHz* |
1 |
X3.17 |
0,1 Hz |
20 kHz* |
2 |
X3.18 |
0,1 Hz |
20 kHz* |
3 |
X3.19 |
0,1 Hz |
20 kHz* |
4 |
X3.20 |
0,1 Hz |
20 kHz* |
5 |
X3.21 |
0,1 Hz |
20 kHz* |
6 |
X3.22 |
0,1 Hz |
20 kHz* |
7 |
X3.23 |
0,1 Hz |
20 kHz* |
8 |
* The frequency sum for all the channels is 40 kHZ
* The maximum frequency value can be reached with 50 % duty cycle.
The following %I variables are provided for each pulse input channel.
Name |
Data type |
Unit |
Description |
Pulse count |
WORD |
|
16-bit value for pulse count. |
Frequency/ Pulse width |
WORD |
0,01 Hz - 1 Hz / 1 us - 1 ms |
Frequency of the input signal. i_GateTime defines the used unit. Measured pulse width. i_GateTime defines the used unit. |
All of these variables are not automatically available, for more detailed description see the following chapters.
Channels 1-8 can be disabled if pulse counting is not needed. PI channels are disabled by default.
The DI status can still be read from the pin's %IX address, see section 3724 PLCopen Addresses.
i_Mode |
IO_MODE_DISABLED |
i_ChannelNbr |
Configured channel number 1,2,..,8 |
i_ResetChnNbr |
No meaning. Use value 0. |
i_ChannelPairNbr |
No meaning. Use value 0. |
i_EdgeSelect |
No meaning. Use value 0. |
i_EdgePolarity |
No meaning. Use value 0. |
i_GateTime |
No meaning. Use value 0. |
Example:
(* Pin 3.21 is disabled. *)
IO_PULSEIN_SET_CONFIG(
i_Mode:=IO_MODE_DISABLED,
i_ChannelNbr:=6,
i_ResetChnNbr:=0,
i_ChannelPairNbr:=0,
i_EdgeSelect:=0,
i_EdgePolarity:=0,
i_GateTime:=0);
In one channel mode, channels 1-8 counts pulses.
i_Mode |
IO_PULSEIN_MODE_1CH |
i_ChannelNbr |
Configured channel number 1,2,...,8 |
i_ResetChnNbr |
No meaning. Use value 0. |
i_ChannelPairNbr |
No meaning. Use value 0. |
i_EdgeSelect |
Selects if channel counts one edge or both edges. 0 = one edge, 1 = both edges |
i_EdgePolarity |
Selects if channel counts rising or falling edge. Meaning only if i_EdgeSelect is 0 0 = falling edge, 1 = rising edge |
i_GateTime |
No meaning. Use value 0. |
Available PI channel values:
Name |
Data type |
Unit |
Description |
Pulse count |
WORD |
|
16-bit value for pulse count. |
Example:
IO_PULSEIN_SET_CONFIG(
i_Mode:=IO_PULSEIN_MODE_1CH,
i_ChannelNbr:=1,
i_ResetChnNbr:=0,
i_ChannelPairNbr:=0,
i_EdgeSelect:=0,
i_EdgePolarity:=0,
i_GateTime:=0);
In two-channel mode, channels 1-8 measure the pulse count for pulse signals which are 90 degrees phase shifted.
Channel A is always the channel with the lower channel number. The pairs can be connected freely but the same channel cannot be used twice.
If the configuration is changed while the application is running, it is recommended to use the initialization function to disable the unused channels:
The initialization must be done for both A and B channels and the pulse count value can be read from the PLC configuration values of channel A and channel B.
The following example demonstrates how to configure channels to 2-ch mode.
i_Mode |
IO_PULSEIN_MODE_2CH |
i_ChannelNbr |
Configured channel number 1,2,...,8 |
i_ResetChnNbr |
No meaning. Use value 0. |
i_ChannelPairNbr |
Channel pair number 1,2,...,8 Cannot be the same as i_ChannelNbr |
i_EdgeSelect |
In 2-ch mode, the channel counts always both edges. In this mode the selection is used to select the counting direction. In normal operating mode, use value 0 (count upwards if channel A is 90 degrees ahead of channel B). Use value 1 to change the counting direction. |
i_EdgePolarity |
In 2-ch mode both edges are counted. In normal operating mode, use value 1 (count upwards if channel A is 90 degrees ahead of channel B). Use value 0 to change the counting direction. |
i_GateTime |
No meaning. Use value 0. |
Available PI channel values:
Name |
Data type |
Unit |
Description |
Pulse count |
WORD |
|
16-bit value for pulse count. Falling and rising edges of both channels increases the counter by one. One cycle increases the counter by 4. |
Example:
(* Use pins 3.16 and 3.17 to count pulses in 2-ch mode.
Pulse count can be read from pins 3.16 and 3.17 PLC configuration values. *)
IO_PULSEIN_SET_CONFIG(
i_Mode:= IO_PULSEIN_MODE_2CH,
i_ChannelNbr:=1,
i_ResetChnNbr:=0,
i_ChannelPairNbr:=2,
i_EdgeSelect:=0,
i_EdgePolarity:=1, (*counting direction is upwards*)
i_GateTime:=0);
IO_PULSEIN_SET_CONFIG(
i_Mode:= IO_PULSEIN_MODE_2CH,
i_ChannelNbr:=2,
i_ResetChnNbr:=0,
i_ChannelPairNbr:=1,
i_EdgeSelect:=0,
i_EdgePolarity:=0, (*counting direction is downwards*)
i_GateTime:=0);
In two-channel DIR mode, the A channel counts the pulses and channel B defines the counting direction.
Channel A is always the channel with the lower channel number. The pairs can be connected freely but the same channel cannot be used twice.
If the configuration is changed while the application is running, it is recommended to use the initialization function to disable the unused channels:
The initialization must be done for both A and B channels and the pulse count value can be read from the PLC configuration values of channel A and channel B.
The following example demonstrates how to configure channels to 2-ch mode.
i_Mode |
IO_PULSEIN_MODE_2CH_DIR |
i_ChannelNbr |
Configured channel number 1,2,..,8 |
i_ResetChnNbr |
No meaning. Use value 0. |
i_ChannelPairNbr |
Channel pair number 1,2,..,8 Cannot be the same as i_ChannelNbr |
i_EdgeSelect |
Selects if A channel counts one edge or both edges. 0 = one edge, 1 = both edges B channel counts always both edges. |
i_EdgePolarity |
Selects if A channel counts rising or falling edge. Meaning only if i_EdgeSelect is 0 0 = falling edge, 1 = rising edge |
i_GateTime |
No meaning. Use value 0. |
Available PI channel values:
Name |
Data type |
Unit |
Description |
Pulse count |
WORD |
|
16-bit value for pulse count. A channel value depends on A and B channel's pulse count. It may rise and fall depending on the count direction in the B channel. When B channel is high, A channel value increases. When B channel is low, A channel value decreases. B channel value includes only the pulse count of the direction channel. It can only rise.
|
Frequency/ Pulse width/ Digital status |
WORD |
Boolean |
A channel: latest counting direction B channel: channel's DI status |
Example:
(* Use pins 3.16 and 3.17 to count pulses in 2-ch DIR mode.
Pulse count can be read from pins 3.16 and 3.17 PLC configuration values. *)
IO_PULSEIN_SET_CONFIG(
i_Mode:= IO_PULSEIN_MODE_2CH_DIR,
i_ChannelNbr:=1,
i_ResetChnNbr:=0,
i_ChannelPairNbr:=2,
i_EdgeSelect:=0,
i_EdgePolarity:=1,
i_GateTime:=0);
IO_PULSEIN_SET_CONFIG(
i_Mode:= IO_PULSEIN_MODE_2CH_DIR,
i_ChannelNbr:=2,
i_ResetChnNbr:=0,
i_ChannelPairNbr:=1,
i_EdgeSelect:=0,
i_EdgePolarity:=0,
i_GateTime:=0);
One of the SW channels (see the table at the beginning of this section) can be configured to reset another channel.
The reset channel resets the pulse counter of the channel which has been configured as the target channel.
The reset channel does not reset the target channel's other values such as frequency or pulse width.
|
When using 2-ch mode, use the IW variable of channel A in application and reset the A channel. |
i_Mode |
IO_PULSEIN_MODE_RESET |
i_ChannelNbr |
Configured channel number 1,2,..,8 |
i_ResetChnNbr |
Target channel number (the channel to be reset) 1-8 |
i_ChannelPairNbr |
No meaning. Use value 0. |
i_EdgeSelect |
Selects if the channel counts and triggers a reset on one edge or both edges. 0 = one edge, 1 = both edges |
i_EdgePolarity |
Selects if the channel counts and triggers a reset on rising or falling edge. Meaning only if i_EdgeSelect is 0 0 = falling edge, 1 = rising edge |
i_GateTime |
No meaning. Use value 0. |
Available PI channel values:
Name |
Data type |
Unit |
Description |
Pulse count |
WORD |
|
16-bit value for reset count. |
Example:
(* Pin 3.18 is used to reset pin 3.16.
Reset count can be read from pin 3.18 PLC configuration. *)
IO_PULSEIN_SET_CONFIG(
i_Mode:= IO_PULSEIN_MODE_RESET,
i_ChannelNbr:=3,
i_ResetChnNbr:=1,
i_ChannelPairNbr:=0,
i_EdgeSelect:=0,
i_EdgePolarity:=0, (*Triggers reset on falling edge*)
i_GateTime:=0);
In frequency mode, channel 1-8 measures frequency and counts pulses.
i_Mode |
IO_PULSEIN_MODE_FREQUENCY |
i_ChannelNbr |
Configured channel number 1,2,..,8 |
i_ResetChnNbr |
No meaning. Use value 0. |
i_ChannelPairNbr |
No meaning. Use value 0. |
i_EdgeSelect |
Selects if channel counts one edge or both edges. 0 = one edge, 1 = both edges |
i_EdgePolarity |
Selects if channel counts rising or falling edge. Meaning only if i_EdgeSelect is 0 0 = falling edge, 1 = rising edge |
i_GateTime |
Frequency is reset if no new pulse edge is detected in given gate time. Value range: 0 - 10 000 ms.
0: frequency is not reset. Frequency unit is 1 Hz. 1 - 99 ms: Frequency unit is 1 Hz. Maximum frequency is 65536 Hz. 100 - 999 ms: Frequency unit is 0,1 Hz. Maximum frequency is 6553,6 Hz. 1000 - 9999 ms: Frequency unit is 0,01 Hz. Maximum frequency is 655,36 Hz. 10000 ms: Frequency unit is 0,001 Hz. Maximum frequency is 65,536 Hz. |
Available PI channel values:
Name |
Data type |
Unit |
Description |
Pulse count |
WORD |
|
16-bit value for pulse count. |
Frequency |
WORD |
1 mHz - 1 Hz |
Frequency of the input signal. i_GateTime defines the used unit.
|
Example:
(* Pin 3.19 is used to measure frequency.
Pulse count and frequency measurement can be read from pin 3.19 PLC configuration.
Frequency unit is 1 Hz and the frequency value is reset if there is no new rising pulse edge in 10 ms
This configuration can be used above 100 Hz frequency. *)
IO_PULSEIN_SET_CONFIG(
i_Mode:=IO_PULSEIN_MODE_FREQUENCY,
i_ChannelNbr:=4,
i_ResetChnNbr:=0,
i_ChannelPairNbr:=0,
i_EdgeSelect:=0,
i_EdgePolarity:=1,
i_GateTime:=10);
In pulse width mode, channel 1-8 measures pulse width and counts pulses.
This mode measures always the pulse width from the rising edge to falling edge.
i_Mode |
IO_PULSEIN_MODE_PULSEWIDTH |
i_ChannelNbr |
Configured channel number 1,2,..,8 |
i_ResetChnNbr |
No meaning. Use value 0. |
i_ChannelPairNbr |
No meaning. Use value 0. |
i_EdgeSelect |
Selects if channel counts one edge or both edges. 0 = one edge, 1 = both edges |
i_EdgePolarity |
Selects if channel counts rising or falling edge. Meaning only if i_EdgeSelect is 0 0 = falling edge, 1 = rising edge |
i_GateTime |
Pulse width is reset if no new pulse edge is detected in given gate time. Value range: 0 - 10 000 ms.
0: Pulse width is not reset. Time unit is 1 us. 1 - 99 ms: Time unit is 1 us. Maximum width is 65536 us. 100 - 999 ms: Time unit is 0,01 ms. Maximum width is 655,36 ms. 1000 - 9999 ms: Time unit is 0,1 ms. Maximum width is 6553,6 ms. 10000 ms: Time unit is 1 ms. Maximum width is 65,536 s. |
Available PI channel values:
Name |
Data type |
Unit |
Description |
Pulse count |
WORD |
|
16-bit value for pulse count. |
Pulse width |
WORD |
1 us - 1 ms
|
Measured pulse width. i_GateTime defines the used unit. |
Example:
(* Pin 3.20 is used to measure pulse width.
Pulse count and pulse width measurement can be read from pin 3.20 PLC configuration.
The pulse width unit is 1 us and the pulse width value is reset if there is no new rising pulse edge in 10 ms
This configuration can be used above 50 Hz frequency with 50% pulse ratio. *)
IO_PULSEIN_SET_CONFIG(
i_Mode:=IO_PULSEIN_MODE_PULSEWIDTH,
i_ChannelNbr:=5,
i_ResetChnNbr:=0,
i_ChannelPairNbr:=0,
i_EdgeSelect:=0,
i_EdgePolarity:=1,
i_GateTime:=10);
Source file Topic000704.htm
Last updated 4-Sep-2025