Ethernet I/O Modules
Built-in Multi-Function I/O
1.
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 on PETL/tET/tPET series include a PWM (pulse
generation) function that can be used to set different frequencie (50 or 100 Hz Max.) and
duty cycles for each digital output channel. In addition, the two digital output channels can
work either independently or simultaneously. 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 remote a controller. In this way, the
tET/tPET/PETL series module reduces the complexity required for the control system
and enhances timing accuracy.
2.
All
Digital Input
modules provide:
Digital input channels that can also be used as 32-bit high speed (3.5 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
:
tET/tPET/PETL
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 tET/tPET/PETL
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.
ICP DAS CO., LTD.
PETL/tET/tPET DIO Series User Manual, Ver. 2.1, Sep. 2014, Page: 12
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