Omron NT-series Programmable Terminal V022-E3-1 - Manual (Page 76)

Caution
Reference
Reference

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Section 2-7
Switching the power ON/OFF when using C200H direct communication
The C200H interface unit has the function of a C200H I/O extension unit. The pow-
er should be switched ON/OFF in the way explained below.
Depending on how the power is switched ON/OFF, the entire system may stop.
Follow the correct procedure when switching the power ON/OFF.
Otherwise the system may operate unpredictably.
Power ON Switch the power ON in the following sequence.
“Connecting to Host” will be displayed on
the NT600S screen. Switch the NT600S power ON
Switch the PC power ON
. . . . . .
After “Connecting to Host” has been dis-
played on the NT600S screen for approx-
imately 1 second, normal operation
starts. . . . . . .

If the power supply to the PC/Host is switched on first, the CPU of the PC/Host is
subject to a system reset, disabling PC/Host operation. If the power to the
NT600S is then switched ON, “Connecting to Host” will be displayed on the
NT600S screen for approximately one second and then normal operation will
commence.

If the I/O connecting cable is disconnected during system operation, an I/O bus
error will occur at the PC/Host side and operation will stop. If this happens, con-
nect the I/O connecting cable and clear the error.
Power OFF Switch the power OFF in the following way.
The next time the power is switched ON,
the NT600S will display the screen that
was
being displayed when it was
switched OFF.
Switch the PLC and NT600S
power supplies OFF simulta-
neously . . . . . .

If the power supply to the NT600S is switched OFF first, the CPU of the PC/Host
is subject to a system reset, disabling PC operation.
 The system must be stopped before replacing a defective NT600S or C200H
interface unit. If only the power to the NT600S is switched OFF, the system will
stop suddenly, causing accidents or damage to machinery.