ICP DAS USA ET-2200 Series, Руководство пользователя

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ET-2200 Series Ethernet I/O Modules
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5. Built-in Multi-function I/O

All Digital Output modules provide:

A Power-on Value (On boot up, the digital output value is set as the Power-on value)

A Safe Value (If Modbus TCP communication is lost for a certain period, the digital output
value will be set as the user-defined safe value)

A PWM Function : The digital output channels support PWM (pulse generation) function
that can be configured with different frequency (100 Hz Max.) and different duty cycle for
each channel. The term “High Duty Cycle” describes the duration of 'on' time in
proportion to the regular interval or 'period' of time. Similarly, the term “Low Duty Cycle”
corresponds to the duration of the 'off' time. Consequently, it is not necessary to keep
switching from ON to OFF from a remote controller. In this way, the ET-2200 series
module reduces the complexity required for the control system and enhances
timing accuracy.
Note: Because of the characteristics of the relay functions, it is recommended that the
PWM on modules with relay functions is not used for extended periods of time.

All Digital Input modules provide:

Digital input channels that can also be used as 32-bit high speed (3 kHz) counters.

High/Low Latched Status Commands: The modules provide commands to read the status
of any digital input channels that are latched high or latched low. The following is an
example that shows the usefulness of the latched digital
input. If we wish to read a key stroke from a key switch
connected to the digital input channel of a module, the
input signal of the key stroke is a pulse signal as shown in
the figure.
If we just use the read digital input status command to read the signal and we cannot
send the command during the B period due to some reasons, then we will lose the key
stroke information. However, with the read latched digital input command, we can still get
the key stroke information even we are not able to send command in B period.

Frequency Measurement : ET-2200 series modules also provide a
frequency measurement function that retrieves the digital input counter value at specific
times and calculates the frequency. Rather than polling via a remote host, the ET-2200
series modules can determine the frequency directly, reducing the communication
delay caused by two ends and also improves the accuracy of the frequency measurement.
In order to applying for more applications, this module provides 3 scan modes and 4
moving average methods for user to select the best way in their applications.