Communicating With The Host; What's The Host Link - Omron NB-series Operation Manual

1 Introduction
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Communicating with the Host

With NB-series PTs, data required for display can be accessed and the words and bits where the
entered data will be stored can be allocated to any area in the PLC. The operations include the direct
reading and writing of the allocated words and bits, the modification of the display status for the
functional objects on the PT screen, and the control and report of the PT status.
NB-Series PTs can be connected to the PLC manufactured by OMRON using the Host Link method.
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What's the Host Link?

The Host Link is a kind of optimized and economical communication method for FA system, which is
applicable to link one PT with one PLC or more. The PC can be used to transfer programs to the PLC,
monitor the data area of PLC and control the operation of PLC.
In the system using Host Link system, one PT sends Host Link commands to the PLC and the
commands' processing is completed followed by returning the results of the processing by the PLC (the
host).
System Features:
Connection method: RS-232C or RS-422A
Transmission rate (baud rate): 4800, 9600, 14400, 19200, 38400, 56000, 57600, 115200 and 187500
bps.
The transmission rates of 14400, 56000 and 187500 bps are not supported by the PLC manufactured
by OMRON.
Host monitoring: The PC can be used to transfer or read the PLC programs, and perform reading and
writing of the data area of PLC.
Error check system: Both parity and frame check are performed to estimate the errors occurring during
all the communications.
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NB-Series PT
NB-series Programmable Terminals NB-Designer Operation Manual(V106)
PLC
DM area
I/O area
Auxiliary area
timers/counters