CheckPort (Check Status of a Control Port)

CheckPort returns the status of a digital terminal.

Syntax

CheckPort ( Port )

In the following example code, the status of control port C1 is checked and the result is stored in the variable PortStat. The port is set by the state of Flag (if Flag is high, the port is set high).

Public PortStat As Boolean
Public Flag As Boolean

BeginProg
  Scan (1,Sec,3,0)
    If Flag
      PortSet (C1 ,1)
    Else
      PortSet (C1 ,0)
    EndIf
    PortStat=CheckPort(C1)
  NextScan
EndProg

Remarks

CheckPort returns True (-1) if the specified digital channel is high or False (0) if the digital channel is low. CheckPort can be used on the right side of an expression (e.g., Variable = CheckPort (Port)) or as an expression. CheckPort has only one parameter:

Parameter

Port

The number of the port to use in this instruction. An alphanumeric code is entered. Right-click to display a list.

Code Description
C1 Control Port 1
C2 Control Port 2
C3 Control Port 3
C4 Control Port 4
U1 Universal terminal 1
U2 Universal terminal 2
U3 Universal terminal 3
U4 Universal terminal 4
U5 Universal terminal 5
U6 Universal terminal 6
U7 Universal terminal 7
U8 Universal terminal 8
U9 Universal terminal 9
U10 Universal terminal 10
U11 Universal terminal 11
U12 Universal terminal 12

Type: Constant

Caution: The value returned may not be valid if using the control port as a serial port or as a pulse counting port.