Hitachi LQE050, Hardware Manual

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4 OPERATIONS
4-3
(3) Transfer stop
Transfers stop depending on the states of the CPU link module and the CPU module defined in
Table 4-1.
Table 4-1 Transfer Stop
State Cause Transmission Reception
Power off The power module is powered off, or the power switch is off. Stopped Stopped
CPU STOP The RUN/STOP switch on the CPU module’s front-panel is
set to STOP. Stopped Enabled
CPU DOWN An internal error occurred in the CPU. Stopped Stopped
CPU reset The reset switch on the CPU module’s front-panel was
pressed. Stopped Stopped
CPU link module
internal error The internal circuit has failed. Stopped Stopped
Unable to transmit The CPU has its transfer area set to zero. Stopped Enabled
(4) Reception timeout
A reception timeout occurs in any of the following conditions:
• Any CPU connected to the link line has been disabled from transmission due to any condition
mentioned in item (3) in Section 4.1, “Transfer.”
• Data has been destroyed (for a consecutive period of 500 ms or longer) due to sequential noise
interference or any other effect.
• The link line cable is disconnected or has defective contact.
When a reception timeout is detected in the G-register area in a CPU, the G-register area is
either held or cleared to zero depending on the clear/hold setting that is entered from the
personal computer.
For information on how to set hold/clear, see Section 5.4 “Setting Up from the Personal
Computer.”
CPU1
G-register area
Transmission stop
Area 1
Area 2
Area 3
CPU2
G-register area
Set hold
Hold area
Area 2
Area 3
CPU3
G-register area
Set clear
Clear area
1 to zero
Area 2
Area 3
Figure 4-2 Clear/Hold Setting