Yokogawa Touch Screen GP20 - Manual (Page 400)

App-24
IM 04L51B01-01EN
Communication Operation
Communication ports are closed when a power failure occurs.
• Reestablish Ethernet connections.
• Client function
• When Modbus client is in use and a power failure occurs in the middle of a
transmission, the data will not be retransmitted.
• When the FTP client function is in use and a power failure occurs in the middle of a file
transfer, the file will be re-transferred when the GX/GP recovers.
• Communication channel values are retained even during a power failure. The GX/GP can
be configured so that the values take on preset values when the GX/GP recovers.
DO Operation
DO output values are not retained during a power failure.
• Alarm output
Alarms are set to off when the GX/GP recovers.
• Manual DO operation
Manual DO operation is set to off, regardless of the condition before the power failure.
Power Recovery Operation Summary
Operation Function Held/Not Held Description
Recording Recording status Held If a power failure occurs during recording,
recording will continue when the GX /GP
recovers.
File creation Held A power failure divides files.
Trend
waveform
File type: Event data
only
Not held Waveforms before the power failure will be
lost.
Trend rate switching Not held Waveforms before the power failure will be
lost.
Other than those above Held Continues to be displayed.
Timer Relative timer Held Timers do not count during the power failure
period.
Absolute timer
Match time timer
Held If timers expire during a power failure,
timeout processing occurs when the GX/GP
recovers.
Remote Remote condition Held If remote conditions change during a power
failure, the corresponding actions are
executed when the GX/GP recovers.
AI channel Moving average Not held When the GX/GP recovers, a new moving
average will start.
Computation Computation condition Held If a power failure occurs during computing,
computing will continue when the GX/GP
recovers.
Computed results Held Data before the power failure is retained.
Rolling average Held Average values before the power failure is
retained.
TLOG Computation Held If absolute timers or match time timers
expire during a power failure, TLOG
computation is performed when the GX/GP
recovers.
Communication Connection Not held Connections need to be reestablished when
the GX/GP recovers.
Client Not held Modbus: Data in transmission is discarded.
FTP: Files in transmission is retransmitted.
Communication channel Held Data before the power failure is retained.
DO Alarm Not held Set to off.
Manual DO Not held Set to off.
Appendix 5 Power Recovery Operation