Yokogawa Data Acquisition with PID Control CX2000 - Manual (Page 373)

App-4
IM 04L31A01-01E
Maximum Number of Data Points per Channel
When the type of data, the number of measurement channels, the number of computation
channels, number of internal control channels, and the number of external control channels
that are to be acquired to the internal memory are determined, the maximum number of
times data can be acquired can be derived from the internal memory size. This number is
referred to as the maximum number of data points per channel.
The maximum number of data points can be derived from the equations in the following table.
Data to Be Saved Maximum Number of Data Points
Display data only 1,2000,000 bytes/(number of measurement CH × 4 + number of
computation CH × 8 + number of internal control CH × 4 + number
of external control CH × 4)
* The maximum number is 100,000.
Display data and event data • Display data
900,000 bytes/(number of measurement CH × 4 + number of
computation CH × 8 + number of internal control CH × 4 + number
of external control CH × 4)
* The maximum number is 75,000.
• Event data
300,000 bytes/(number of measurement CH × 2 + number of
computation CH × 4 + number of internal control CH × 4 + number
of external control CH × 4)
* The maximum number is 30,000.
Event data only 1,200,000 bytes/(number of measurement channels × 2 + number
of computation channels × 4)
* The maximum number is 120,000.
Maximum Sampling Length
The maximum sampling length can be determined from the time it takes to acquire the
maximum number of data to the internal memory using the following equation.
Maximum sampling length = maximum number of data points × sampling interval
Calculation Example of Maximum Number of Data Points and Maximum Sampling Length
• Display Data Only
Measurement channel: 2, computation channel: none, internal control channel: none,
external control channel: none.
Data Maximum Number of Data Points and Maximum Sampling Length
Display data Maximum number of data points = 1,200,000/(2CH × 4 bytes + 0 × 8 bytes + 0 × 4
bytes + 0 × 4 bytes) = 150,000
However, the maximum is limited to 100,000 data points. Therefore, the
maximum number of data points = 100,000.
When the display update rate is 30 min/div (60-s sampling interval)
Maximum sampling length = 100,000 data points Ч
Ч Ч Ч Ч 60 s = 6,000,000 s
(approx. 69 days)
Measurement channel: 3, computation channel: 6, internal control channel: 6, external
control channel: 3.
Data Maximum Number of Data Points and Maximum Sampling Length
Display data Maximum number of data points = 1,200,000/(3CH Ч Ч Ч Ч Ч 4 bytes + 6 Ч Ч Ч Ч Ч 8 bytes + 6 Ч Ч Ч Ч Ч
4 bytes + 3 Ч Ч Ч Ч Ч 4 bytes) = 12,500
When the display update rate is 30 min/div (60-s sampling interval)
Maximum sampling length = 12,500 data points Ч
Ч Ч Ч Ч 60 s = 750,000 s (approx. 8 days)
• Event Data Only
Measurement channel: 4, computation channel: none, internal control channel: none,
external control channel: none.
Data Maximum Number of Data Points and Maximum Sampling Length
Event data Maximum number of data points = 1,200,000/(4CH × 2 bytes + 0 × 4 bytes + 0 × 2
bytes + 0 × 2 bytes) = 150,000
However, the maximum is limited to 120,000 data points. Therefore, the
maximum number of data points = 120,000.
When the sampling interval of event data is 1 s
Maximum sampling length = 120,000 data points Ч
Ч Ч Ч Ч 1 s = 120,000 s (approx. 33 hours)
Appendix 1 Supplementary Explanation of the Acquisition of Display Data/Event Data to the Internal Memory