ET-2200 Series Ethernet I/O Modules
Copyright © 2020 ICP DAS CO., Ltd. All Rights Reserved.
-7 -
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.
