YOKOGAWA SMARTDAC+ GX20, User Manual

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App-22
IM 04L51B01-41EN
[Reference] Simple calculation method of the data acquisition interval
A simple calculation method of the data acquisition interval using wireless devices is shown
below. Note that the value derived with this method is an approximation (with 10% duty limit
considered), but this value may vary greatly depending on the radio environment.
The calculation does not take into consideration the retransmission of data acquisition
requests due to timeout and the like.
Table 5.9 shows the reference command response time for reading the data of a single
command by a router from the coordinator.
Table 5.9 Reference command response time
For GX20/GM10
Number of readout channels Reference command response time (ms)
1 210
10 220
20 230
40 250
60 270
80 290
100 310
120 330
125 335
For UT52A/UT32A
Number of readout channels Reference command response time (ms)
1 394
25 490
100 790
Note:
• The above shows the reference command response times when the data type is INT16. If
the data type is INT32 or FLOAT, double the values shown above.
• If communication is performed via repeaters, add a 80 ms delay for each hop.
A calculation example of the data acquisition interval is shown below.
Coordinator
Router1 Router2 Router3 Router3
Example 1
Coordinator
Router1 Router2
Example 2
Coordinator
Router1
Example 3
Fig. 5.12 A calculation example of the data acquisition interval
Example 1
If data is acquired from three routers (router 1, 2, and 3) and the number of channels of
each router is 10, 20, and 40, respectively, the data acquisition interval is given by
Data acquisition interval = 220+230+250 = 700 (ms)
Therefore, data acquisition is possible at a read cycle of 1 s or more.
Example 2
If data is acquired from three routers (router 1, 2, and 3), the number of channels of each
router is 10, 20, and 40, respectively, and router 2 is used as a repeater for router 3, the
data acquisition interval is given by adding an 80 ms delay per hop as follows:
Data acquisition interval = 220+230+250+80 = 780 (ms)
Therefore, data acquisition is possible at a read cycle of 1 s or more.
Appendix 5 System Operation Considerations