Yokogawa DAQWORX - Manual (Page 116)

3-3 IM WX103-01E
1
2
3
4
5
Index
V
ewer
Synchronzaton
The Logger of the MXLOGGER or the Integration Monitor of the MX100 Standard
Software sends PC’s time information to the MX100 at measurement intervals. The PC’
s time information is received along with the measured data when the data is received
from the MX100. When measured data is recorded, the PC time information (the MX100’
s time information is used on the monitor display of the Logger) is also recorded.
PC Time
MX100
Packet
Packet
Measured data
Measured data
PC Time
. . . . . .
PC Time
MX100
PC
MX100
On the other hand, each MX100 makes measurements based on the main module clock.
Therefore, the PC’s time that is recorded with the measured data and the PC’s time when
measurements were made may be offset. When loading the data, the Viewer can process
the time information to match the PC’s time that was present at time of measurement.
This process is called
synchronization (for details, see Note on the next page).
Note
• Details of Synchronization
Given M recorded data points of a given channel of a data file that has not been
synchronized, synchronization (linear interpolation) is carried out as follows:
1. From the record start/stop time and record interval, determine N, the number of data
points that will result after synchronization of the relevant channel.
2. From the record start time and record interval, determine Stn (n=0, ... , N-1), the PC time
after synchronization of each data point.
3. From the record start/stop time and the PC millisecond clock counter values at record
start/stop, determine PCcntPerms, the clock counter value per millisecond.
4. From the PC millisecond clock counter values recorded with the data before
synchronization and PCcntPerms, determine Rtm (m=0, ... , M-1), the PC time of the
data before synchronization.
5. Determine m such that the expression Rtm-1 ≤ Stn < Rtm is satisfied and retrieve the
data values before synchronization VRtm-1 and VRtm at the PC time of Rtm-1 and Rtm.
6. Determine the data values after synchronization from the expression VStn = (Stn –
Rtm-1) × (VRtm – VRtm-1)/(Rtm – Rtm-1) + VRtm-1 where (n=0, ... , N-1 and m=0, ... ,
M-1).
7. Determine the data values after synchronization for N data points, and then write them to
the synchronized file.
Rt m-2
VRt m-2
VRt m-1
VSt n
VRt m
VRt
m+1
Rt m-1 S tn R tm Rt m+1 PC time
Data value
• When loading a data file saved by the MX100 to the CF card, synchronization is not possible
because the PC time information needed in the data synchronization is not present.
3.1 Loadng Data Fles