Host Link; Nt Link - Omron NT631 Series Reference Manual

Communications with the Host

1-4-2 Host Link

1-4-3 NT Link

Features of the NT Link
22
Downloaded from Elcodis.com electronic components distributor
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 types.
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/CS1H-E(V1), 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
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/CS1H-E(V1).
The 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/CS1H
PCs.
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 types of PCs can be executed. The
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 to which a touch switch has been allo-
cated to be allocated 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 to touch switches in this area cannot be used for other pur-
poses.
• 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.)
• In the case of PTs that support the standard 1:N NT Link (NT20S, NT31,
NT31C, NT600S, NT620S, NT620C, NT625C, NT631, NT631C) up to 8 PTs
can be connected to one port of the PC and used at the same time. Up to 8 PTs
(NT31, NT31C, NT631, and NT631C) can also be connected simultaneously
when the high-speed 1:N NT Link is being used. All of the PTs connected to a
PC port must use either the standard or high-speed 1:N NT Link; the two com-
munications systems cannot share a single port.
Section 1-4