(4) Reserved tag
Tags can be reserved.
A tag set as a reserved tag is not used to perform Tag communication. It is used only
to reserve input area and output area.
(b) Setting method
(c) Checking reserved tag settings in the buffer memory
(a) Data type of the target device
(b) Tags that can receive read or write requests
(c) Time required to recognize the Application Trigger request
(d) When the data transmission delay is lengthened
Adding a tag (canceling the reserved tag setting) does not require a sequence
program change since input area and output area remain unchanged.
A sequence program change is not necessary by setting (not deleting) the tag as
a reserved tag when a tag is no longer used.
Select "Reserved Tag" in the "Message Tag" window of Utility Package. (
Parameter setting and program example in this section)
The reserved tag setting status can be checked in Reserved
tag(Class3/UCMM)(Un\G27216 to Un\G27231).
The data type of the EtherNet/IP module must match that of the target device.
For the Data Type other than INT or DINT, register and set it using the "User
Define" window. (
Section 7.9.5 "User Define" window)
Only the tags set as "Target" in "Class3/UCMM Tag Parameter" can accept the
Tags set as "Originator" do not accept any request from the other device.
(Class3/UCMM)(Un\G27072 to Un\G27087)
A maximum of 10ms is required after the Application Trigger request
(Class3/UCMM)(Un\G27072 to Un\G27087) is set to on.
When the line is highly-loaded or unstable, the ACK of TCP from the target device
may not be receivable.
In this case, the EtherNet/IP module sends the data after 10 seconds which
lengthen the transmission delay time by 10 seconds from normal delay time.
If the above case frequently occurs, check the connectivity of cables and take
measures such as reducing the line load by increasing the setting value of RPI.
4.2 Tag Communication Function
4.2.3 UCMM Tag communication