示例：ChartMode Automatic

Option Explicit
Dim pen1, pen2 As Pen
Private Sub Form_Load()
Dim Ps As Pens
Set Ps = Trend1.Pens
Set pen1 = Ps.Add("Tag0", "Temp 1", "Deg F", 0, 100)
Set pen2 = Ps.Add("Tag1", "Pump 1", "Volts", 0, 100)
Trend1.RefreshRate = 1000
Trend1.ChartMode = rstAutomatic
End Sub
Private Sub Temp1_Changed(newTemp1 As Long)
' This routine only has to run when Temp1 changes.
' The chart will reflect the new value on the next refresh.
pen1.Value = newTemp1
End Sub
Private Sub Pump1_Changed(newPump1 As Long)
' This routine only has to run when Pump1 changes.
' The chart will reflect the new value on the next refresh.
pen2.Value = newPump1
End Sub
' Some buttons to make the graph change.
Private Sub Command1_Click()
Temp1_Changed (Rnd * 100)
End Sub
Private Sub Command2_Click()
Pump1_Changed (Rnd * 100)
End Sub
Private Sub Trend1_RefreshRateExpired()
Static n
Label1.Caption = n & " points"
n = n + 1
' NOTE: The number of points actual stored is limited
' to the number on the screen, plus the number in the
' BufferSize property.
End Sub