Yokogawa DAQWORX - Manual (Page 30)

3-7 IM WX1-05E
1
2
3
Index
Deta
led Descr
pt
on Funct
ons
In this case, as much time as possible must be given to interval ∆T to acquire all tags
assigned to the port.
• When data readng tmes out due to such nstances as nose nterference durng
communcaton, or when a Modbus devce’s power turns OFF
In the figure below, with the data reading at time T, the reading of all tags occurs
within the logging interval ∆T, but with data reading at time T1, TAG0003 times out,
and data reading at time T2 is dropped.
TAG001
TAG002
TAG003
TAG004
TAG001
TAG002
TAG004
T T1 = T + ∆ t T2 = T + ∆ t x 2 T3 = T + ∆ t x 3
Interval: ∆ T
Data reading at time T Data reading at time T1
TAG003 times out
Data
dropout
occurs
Time
Time
Timing of Data Reading
Enter as short of a timeout time as possible, keeping in mind the processing power and
baud rate of the Modbus device performing communications with GateMODBUS. As you
can see from the figure above, if the timeout time is long data can be dropped not only
from tags that timed out, but also from adjacent tags even if they would have responded
normally.
Tmeout Operaton
When reading tag data, after sending a register value request message to the Modbus
device, if the message is not received within the specified timeout time that tag is
considered to have timed out. When the setting of “Retry Use” is turning on, retrying is
executed for tag which have timeout.
Resettng the Tmeout Counter
You can reset the timeout counter for the executable function from the configurator.
When resetting the timeout counter, the retries of tags for which data acquisition was
stopped due to the executable function having timed out begin again at 1, and data
reading is performed.
3.2 Detaled Descrpton of Functons