18.17.2 Restrictions for Historical Trend Graphs

• For Historical Trend Graphs, Data Block Display Graphs, XY Historical Scatter Graphs and XY Block Display Scatter Graphs, you can display up to 8 graphs on a single screen (including called screens and popup windows) at the same time.

• For Historical Trend Graphs, Data Block Display Graphs, XY Historical Scatter Graphs, and XY Block Display Scatter Graphs, you can display up to 40 channels on a single screen simultaneously (including called screens and popup windows). Any subsequent channels do not display.

• The maximum number of channels (number of lines) that can be displayed on a single Historical Trend Graph is 20.

• In the normal display, the graph display area is updated when a graph scrolls over or is erased (sampling data is cleared). In the pen recorder display, every time data is sampled, the display is updated. When the display is updated, the graph display area is filled in with a clear color and then the graph is displayed again. Therefore the screen may flicker.

• Coordinate points of the graph data are calculated as a value between 1 and 1000. Even though values may be outside the display range, if the converted values are within range, they will display in the graph.

• Do not draw other parts in the graph display area. To draw pictures such as lines directly within the display area, place the graph on base screen 9000 to 9999. If you draw scale lines within the graph display area on base screens 1 to 8999, the scale lines will not show on the display unit. To display a graph with scale lines on base screens 1 to 8999, load screen 9000 or higher.
  On screen 9000 or higher, draw the graph and objects that overlay the graph. Other parts such as switches may not operate properly.

• When using the graph area color with a graph with no shape on base screen 9000 or higher, drawing is done in the following order. As a result, if you draw on the graph display area, or you set the base screen's background color, these draw with a higher priority than the Graph Area Color.

  1. Graph Area Color

  2. Drawings such as Line or Rectangle, or Base screen background color

  3. Line Chart

• When the sampling period is specified as 1 second or less, depending on the size of the graph display area used, scroll processing can take almost one second, and communication and tag processing can be affected.
  In this case, setting the sampling period to two or more seconds should correct the problem.

• If an error occurs when reading data samples, the line on that portion of the graph will not display. If the error continues, the graph display will not display for that period. Similarly, when you use the thin out display (zoom), thinned out data with read errors will not display.
  When the next sampled data displays on the historical trend graph, it displays as follows.
  

• If the [Data Type] is set to [BCD] and data containing A to F(h) is stored as sampled data, the previous value will appear in the graph display. If the first sampled data is not BCD, it will show "0" in the graph display.
  When the next sampled data displays on the historical trend graph, it displays as follows.
  

The fourth sample, 95(5Fh) is ignored, and the third sample, 50(32h), is shown in its place on the Graph.

• If the [Data Type] is set to [BCD], and there is a read error for data prior to samples containing A to F(h), the graph display is stopped from the data before the read error occurred until the next valid data. As a result, data that includes A to F(h) will display in the graph with the last valid value before the read error. If a valid value does not exist before the read error, the graph will not display for that period.

• If you display historical data when the [Data Type] is set to [BCD] and sampled data includes A to F(h), the graph will not display.
  When the next sampled data displays on the historical trend graph, it displays as follows.
  

• Set the [Data Type] on the Historical Trend Graph to match the data sample bit length. If the [Bit Length] is set to [16 Bit] and the [Data Type] is 32 bit, two Words' data are combined and handled as 32 bit.
  
  In sampling settings, when [Bit Length] is [32 Bits] and the historical trend graph is 16 bits, display data only from the bottom 16 bits.

• If you have selected [Enable multiple data types] in the [Address] tab (Common Settings [Sampling]), you can display graphs for data with [Word 16 Bit] and [Word 32 Bit] data types. You cannot display graphs for any other data types.

• When [Display Range] is set to [Address] and a communication error occurs, drawing is done using a value of [0].

• When the auxiliary line is set to [Address] and a communication error occurs, drawing is done using a value of [0].

• When the [Display Condition] is set to [Display When Bit ON] and a communication error occurs, the graph will not display. When using [Display When Bit OFF] and a communication error occurs, the graph will continue to display.

• If there are multiple Historical Trend Graphs with the same Parts ID on the same screen, the graph that was placed will be considered valid. The second graph will not be displayed. The same is true for when loading the screen using Call Screen--the graph that is placed first will be displayed while the second graph will not be displayed.

• When the number of sampling is 1, Thin Out Mode is disabled.

• When you define [Alarm Analysis Settings] from the [Common Settings] menu's [Sampling] settings, operations on historical trend graphs drawn on the [Alarm Analysis Screen] will be different. For more details, please refer to the following.
  19.11.3 About Alarm Analysis

Restrictions on Displaying Historical Data

• Only one Historical Trend Graph part with a Display Historical Data function enabled can be placed on a Base screen.

• The Display Historical Data function does not work.

• The Number of Data (current data + historical data) that can be displayed in one channel with Display Historical Data is the amount in [Cycles] specified in the sampling settings.
  For the Historical Trend Graph [Data Samples], set a number less than [Cycles] in the sampling settings.

• In the [Sampling Settings]'s [Mode] tab, when the [Retain Sampling Data (SRAM)] check box is cleared, the display unit's sampled data is erased when turning off the display unit, resetting the display unit, or transferring a project. You cannot display erased historical data. If you want to display historical data after a power shutdown or resetting the display unit, select the [Retain Sampling Data (SRAM)] check box.

• The number of sampled data that you can save in the display unit differs depending on the display unit model and the sampling settings.
  24.14.1 Usage Capacity of Sampled Data
  The table below shows the number of channels and samples when saving to backup memory only sampling groups used with trend graphs.

  The maximum number of samples per Number of Channels

  Backup Memory Size	1 Channel	10 Channels	20 Channels	30 Channels	40 Channels
  320 KB	65535	16265	8132	5421	4065
  128 KB	32180	6435	3217	2144	1608

  Description

  Number of Sampling Groups = 1, Blocks = 1, Data Type = 16 Bit, Overwrite old data after finishing the specified cycles, No Date Data, No Data Enabled/Disabled flags

• If you change the time on the display unit clock, the graph may not display correctly.

• To display the sampled data on a different display unit, the sampling group settings in both display units must be the same.

• When using the following models and sampling data is backed up to external storage, the index file "TSAMPINDEX.idx" is generated. If there are no index files, the display of historical data is slower than if the index file is available as the display unit has to reference the particular backup file.

• SP5000 Series

• GP4000 Series

• GP6000 Series

• ST6000 series

• ET6000 Series

• STM6000 Series

• STC6000 Series

• GPH6000 Series

• When using a model that automatically creates index files, the display of historical data in copied backup files is not possible, even if you copy backup files from other display units with the same sampling settings.

  To display historical data in copied backup files, either delete the index files or save in locations other than the sampling group folders. When there are no index files in the folder and data is backed up, new index files are created and index files moved to other locations are not updated.

• Do not use two different types of switches for the same Historical Trend Graph. The switch will not operate normally. For each Historical Trend Graph, set up no more than one [Historical Data Display] switch.

• When using a Switch Lamp [Special Switch] - [Historical Trend Graph Switch] for Display Historical Data, place the Special Switch and the trend graph with the Display Historical Data function on the same Base screen. If the Historical Trend Graph is placed on the Base Screen and the Special Switch on the Window Screen, they will not function.

• If you do not select the [Show Cursor] check box of the historical trend graph, it is not possible to display historical data of sampling data stored in the external storage.

Show Cursor/Time Display/Historical Data Search Feature Restrictions

• Set up the following to use Show Cursor, Time Display and Historical Data Search features.

• From the [Common Settings] menu's [Sampling] settings, open the [Mode] tab and select the [Retain Sampling Data (SRAM)] and [Back Up Sampling Data] check boxes.

• From the [Common Settings] menu's [Sampling] settings, open the [Mode] tab and in the [Extended] settings select the [Add Time Data] check box.

• In the Historical Trend Graph, open the [Display Historical Data] tab and select the [Show Cursor] check box.

• Do not draw a Historical Trend Graph with the [Selected Time] check box selected, and a Special Data Display [Show CSV] or a Sampling Data Display part with the [Edit Data] check box selected, on the same screen.
  Drawing these objects on the same screen prevent the Sampling Data Display's [Edit Data] function from working. The [Selected Time] display or Special Data Display [Show CSV] will work only on the first set up part.

• While entering the date/time for a historical data search, you cannot input data into Data Displays set up with the [Allow Input] option. Similarly, while inputting data into the Data Display, you cannot enter the date/time for a historical data search.

• When Historical Trend Graph’s [Show Cursor] is enabled and the [Graph Area Color] is set to the same color as the cursor color ([E7] for models that support color, [8] for models that support monochrome), or similar color, the cursor may not be visible on the graph. If this is the case, set the [Graph Area Color] to a different color.