Omron ETHERNET DIRECT DR 170 14 - Manual (Page 27)

Klinkmann Automation Omron Ethernet DAServer 25
Omron Ethernet DAServer Ver 1.x User Manual Rev 1.4 17014m14
• Check or uncheck the Slave Mode check box to select the principles how to obtain
data from corresponding controller. If Slave Mode is not checked (Master mode) –
DAServer polls data from controller all the time. In Slave Mode (if checked) -
DAServer requests data from Controller only once – at communication start-up -
and then only waits for unsolicited messages from controller (writing to controller is
still supported). Communication status is considered as good even if there is no
unsolicited data received. To get more reliable communication status in Slave
Mode – activate the Watchdog message processing (details see later in this
chapter) or time-by-time write values to PLC. With Watchdog activated –
Controller’s communication status depends on success of Watchdog messages.
Default processing mode is Master mode.
• Enter the necessary setting in Gateway Count (GCT) field (the default setting is
2). GCT setting specifies the number of allowed bridge passes in FINS commands
sent to PLC; for example, GCT=7 is needed to support new CS/CJ-series CPU
Units with Unit Ver. 2.0 or higher.
• If necessary – configure Watchdog. The Watchdog would be useful in case the
PLC internal program needs to check, whether there is communication with
computer where Omron Ethernet DAServer is runnung or not. With Watchdog
activated, DAServer time-by-time writes some predefined value (e.g. 255) into
predefined address in PLC’s memory (e.g. into D100). At the same time the PLC
program must periodically check the current value in this memory address. If value
is equal to Watchdog’s predefined value, then PLC’s program considers
communication Status as Good and resets the check address to different (non-
predefined) value, e.g. to 0. (It will allow to program to check communication state
the next time.) If value differs from predefined, then PLC’s program considers
communication Status as Bad.
Note: Because of time synchronizing problems with PLC and PC it is recommended to
consider the communication Status as Bad only after few consecutive test value
mismatch cases, not immediately after the first mismatch.
To activate the Watchdog processing - set Watchdog Time Interval to non-zero value.
Value entered in this field indicates the frequency (in seconds) the DAServer sends
Watchdog message to corresponding PLC. This value must be a bit less as time interval
the PLC program checks the value in watchdog address in the PLC.
Enter Address to Write field to indicate the watchdog address in PLCs memory that is
used as Watchdog check address. Address to Write must be a valid item/point name
(see Item Names section.)
Note: Use only Word memory areas for Watchdog. Do not take addresses not presented
on current PLC configuration. Do not take addresses, used as PLC system areas
or in PLC’s program logic. Do not use specific areas, such as Step Area Present
Values in CV-series PLCs, or IR or DR areas in CS1-series. If DAServer does not
accept memory area for Watchdog – you will see error logging in ArchestrA
System Management Console’s Log Viewer.
Enter integer from 0 to 65535 into Value to Write field to set Watchdog predefined value.
The same value PLC program expects to see in Watchdog check address.