Yokogawa Data Acquisition with PID Control CX2000 - Manual (Page 371)

App-2
IM 04L31A01-01E
Overwriting of the data to the next block is repeated each time the trigger
condition is met while the CX2000 is in the trigger-wait state. To stop the
acquisition of the event data, press the [STOP] key.
Data acquisition
Trigger wait
Trigger condition
met
1st block
Data acquisition
Trigger wait
Trigger condition
met
2nd block
Data acquisition
Trigger wait
Trigger condition
met
Last block
Note
• You can check the event data information in the internal memory using the memory
summary.
• If a power failure occurs, the event data in the internal memory is closed as a single file.
Pre-trigger of Event Data
You can set the pre-trigger when the acquisition mode of event data is set to [Trigger] or
[Rotate].
It is a function used to save the data before the point where the trigger condition is met
as event data. This function is convenient when you wish to view the data before the
occurrence of a certain event such as when an alarm occurs.
Specify the pre-trigger as a percentage (0, 5, 25, 50, 75, 95, or 100%) of the acquisition
time of the event data. If set to 0%, the entire data is the data existing after the trigger
condition is met. The initial value is 0%.
Trigger Type of Event Data
You can set the type when the acquisition mode of event data is set to [Trigger] or [Rotate].
You can select the type of trigger used to start the acquisition of the event data from the
following. If you specify multiple trigger types, OR logic is applied to the triggers. Thus,
if any of the trigger conditions are met, event data acquisition is started.
Type Description
Key trigger The trigger condition is satisfied when the FUNC > [Trigger] soft key or the
USER key (only when the “trigger” function is assigned to the USER key) is
pressed.
External trigger If [Trigger] is assigned to the remote control terminal, the trigger condition is
satisfied with a remote input.
Alarm trigger The trigger condition is satisfied when any of the alarms occur.
Number of Data Points That Can Be Acquired to the Internal Memory and Sampling Length
This section describes the number of display data and event data points that can be
acquired to the internal memory and the sampling length. The information can be used
to estimate the time until the internal memory becomes full or used to determine the
number of channels and sampling interval for saving the data.
For the auto save interval of display data and sampling length of event data, a selectable
range of values are assigned to the soft keys and displayed based on the information
described here.
Number of Bytes per Channel
Display data consists of minimum and maximum values for each sampling interval.
Event data consists of instantaneous values.
The number of data bytes per channel is shown in the following table.
Data Type Measurement Channel Computation Channel
Display data 4 bytes/channel 8 bytes/channel
Event data 2 bytes/channel 4 bytes/channel
Appendix 1 Supplementary Explanation of the Acquisition of Display Data/Event Data to the Internal Memory