Host Link; Nt Link - Omron NT21 Reference Manual

Communications with the Host

1-4-2 Host Link

Reference: The CPU Unit cannot be changed to RUN mode when the PT is connected to a

1-4-3 NT Link

Features of the NT Link
The area to control and notify the PT statuses, including display screens, dis-
play/no display status, and buzzer output, can be freely allocated in any part of
the PC data area. This means that the PC status can be read and controlled
just by reading this area at the PC side, without preparing a special commu-
nication program.
The direct connection function allows the PT to directly read and write almost all
bits and words in the PC and to automatically change the PT screen display. This
function can reduce the load on the PC so that its program development efficien-
cy is improved.
The host is connected to a PT in a 1:1 connection, and the words and bits of the
host are read and displayed by host link communication. This method can be
used for connection to the majority of PC models.
PC using Host Link communications. Use a C200H-PRO27 or CQM1H-PRO01
Programming Console. The Programming Console will display a password input
screen when the Programming Console is switched to specify RUN mode. To
switch the CPU Unit to RUN mode using communications, change the commu-
nications mode with the PT to NT Link mode.
NT Link is a method for high-speed communication with a PC using the direct
connection function. The PCs that can be connected with the NT Link are as fol-
lows:
CPM1, CPM2A, CPM2C, CQM1, CQM1H, C200HS, C200HX/HG/HE(-Z)E,
CS1G/H/D, CJ1G/H/M, CVM1/CV-series PC (-EV1 or later version), SRM1
Besides the 1:1 NT Link method, in which one PC is connected to one PT, the
NT21, NT31/NT31C, and NT631/NT631C can also use the 1:N connection NT
Link method, which allows a maximum of eight PTs to be connected to one PC
port.
PCs that can be connected with the 1:N connection NT Link method are as fol-
lows: CQM1H, C200HX/HG/HE(-Z)E, CS1G/H/D, CJ1G/H/M.
The NT21, NT31/NT31C, and NT631/NT631C also support OMRON's high-
speed 1:N NT Link that provides faster 1:N communications. The only PCs that
support the high-speed 1:N NT Link are the -EV1 and higher versions of the
CS1G/H/D, CJ1G/H/M.
In the following sections, the term NT Link is used to refer to the NT Link commu-
nication method in general, the term 1:1 NT Link is used to refer specifically to
NT Links with a 1:1 connection, and the term 1:N NT Link is used to refer to both
standard and high-speed NT Links with 1:N connections. When necessary, the
standard 1:N NT Link is distinguished from the high-speed 1:N NT Link.
The NT Link has the following features.
High-speed communications with specific models of PCs can be executed.
The NT21, NT31/NT31C, and NT631/NT631C also support OMRON's high-
speed 1:N NT Link.
Writing in units of bits to the PC memory area is possible.
This enables the other bits of words allocated for a touch switch to be allo-
cated for other purposes (e.g. a lamp).
However, since data is written to the DM Area in word units, the other bits of
words allocated for touch switches in the DM Area cannot be used for other
purposes.
The NT Link can be used even when the PC is in the RUN mode. (When the
host link method is used, the PT switches to the monitor mode when the PC is
in the RUN mode.)
Section 1-4
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