TrnPlot
Prints the trend line of one or more trend tags. Each trend line is drawn with a different pen style and marker as appropriate. The trend plot includes a comment and a legend, and you can specify the vertical high and low scales. The Mode defines the color mode of the printer. The default mode is black and white.
For more advanced trend plotting, you can use the low-level plot functions.
Syntax
TrnPlot(sPort, nSamples, iTime, rPeriod, sTitle, AN, Tag1......Tag8, iMode, sComment, rLoScale1, rHiScale1, ......rLoScale8, rHiScale8)
sPort:
The name of the printer port to which the plot will be printed. This name needs to be enclosed within quotation marks. For example LPT1:, to print to the local printer, or \\Pserver\canon1 using UNC to print to a network printer.
nSamples:
The number of data points on the plot.
iTime:
For periodic trend or event trends displayed as periodic:
The end point in time (the latest point) for the trend plot.
For event trend type:
The event sample number (e.g. using TrnGetEvent)
rPeriod:
The period (in seconds) of the trend plot. This can differ from the actual trend period.
If you omit the period, it defaults to the sample period of Tag1.
sTitle:
The title of the trend plot.
Tag1. . .Tag8:
The trend tags.
AN:
The AN of the chosen trend. If you enter 0 (zero), the display mode will default to 258. (This is the display mode that is passed into TrnGetTable() when it is called internally by TrnPlot().) If you call TrnPlot() from a report, you need to enter 0 (zero) here.
iMode:
The color mode of the printer.
0 - Black and White
1 - Color
sComment:
The comment that is to display beneath the title of the trend plot. You may pass an empty string if no comment is required.
rLoScale1, HiScale1,......LoScale8, HiScale8:
The minimum and maximum on the vertical scale for the trend line of each of the tags (Tag1. . . Tag8).
Return Value
0 (zero) if successful, otherwise an error is returned.
Related Functions
TrnComparePlot, TrnPrint, PlotOpen, SPCPlot
Example
/* Prints a black and white plot to LPT1, containing the trend lines of two variable tags (PV1 & PV2). The trend lines have a starting time of 9am, on 11/10/96, 200 sample points, and a period of 2 seconds. The trend line of PV1 will be on a vertical scale of 0-200, and PV2 will be on a vertical scale of 0-400. */
INT time;
Time = StrToDate("11/10/96") + StrToTime("09:00:00");
TrnPlot("LPT1:",200,Time,2,"Citect Trend Plot","PV1","PV2","","","","","","",0,"Process variable operation at shutdown",0,200,0,400);
See Also