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Checking Operations for CS-series, C200HX/C200HG/C200HE-(Z)E, and C200HS Master Units
Section 6-2
6-2-3
Checking Normal Operations Using Ladder Programs
This section provides information on how to write a ladder program to monitor
the operation of the CompoBus/S System and prohibit using the I/O data of
the Slaves in the system when an error occurs.
To write a ladder program for CompoBus/S remote I/O communications for the
CS-series, C200HX, C200HG, C200HE-(Z)E, or C200HS Master Unit, it is
recommended to write I/O data on condition that the Active Node Flags and
Communications Error Flags in the status area are monitored to check the
operation of the CompoBus/S System.
The CompoBus/S status area has the following flags. (Refer to page 81.)
Active Node Flags:
Once a Slave joins the CompoBus/S network after the Slave is turned ON,
the Active Node Flag corresponding to the Slave will be ON.
Communications Error Flags:
If a Slave in the network fails to communicate with the Master, the Commu-
nications Error Flag corresponding to the Slave will be ON. After the Com-
munications Error Flag is ON, the previous input data from the input Slave
will be kept on hold. While the Communications Error Flag is ON, the input
date of the input Slave is not reliable. (The program will be executed with
the previous data.)
The following ladder program example uses I/O data after checking the nor-
mal operation of the CompoBus/S System. In this example, the C200HX Mas-
ter with unit number 0 is used and usable node numbers are IN0 to IN7 and
OUT0 to OUT7.
