BECKHOFF BC8000 - Manual (Page 29)

Appendix
BC8000 29
Programming Example
Local variables in program
MAIN PROGRAM MAIN
(* Program description
*)
(* The BC8000 sends a word of output data every 500ms to a BK8000 *)
(* at that time the low byte is always incremented by one
*)
(* The BK8000 then returns a word of input data *)
(* The BC8000 analyzes this, shifts the byte one bit to the left and *)
(* again outputs it on its output terminals. Required hard/software: *)
(* 1 x BC8000,1 x KL1104, 2 x KL2114, 1x 9010, 1 x BK8000, *)
(* 2 x KL1104, 2 x KL2112, 1 x KL9010 *)
(* Communications Lib, serial cable with two D-sub plugs *)
VAR
ComControl : KL6Control5B; (* function bloc for automatic *)
(* communication *)
Receive: ReceiveByte; (* function bloc for receiving data *)
Send: SendByte (* function bloc for sending data *)
Sb: BYTE;
Senden:ARRAY[0..6] OF BYTE;
start: BOOL; (* auxiliary variable set to FALSE for the first cycle *)
i2: USINT;
i3: USINT;
Summe: BYTE; (* checksum *)
Timer1: TON; (* starts transmission every 500 ms*)
Starten: BOOL; (* set TRUE every 500ms until all *)
(* data have been sent *)
J0: UINT;
t1: INT;
byAusgang1:ARRAY[0..20] OF BYTE;
EingWorte: USINT;
END_VAR
MAIN program
ComControl
Sending
IF NOT start THEN (* Initialization of the array for the BK8000 protocol *)
senden[0]:=16#50; (* start marker *)
senden[1]:=16#01; (* number of words to be sent *)
senden[2]:=16#11; (* message ident *)
senden[3]:=16#0B; (* coupler address *)
senden[4]:=16#FF; (* DO *)
senden[5]:=16#FF; (* D1 *)
senden[6]:=16#6B; (* checksum *)
Start:=TRUE;
END_IF
(*++++++++++++++++++++++++++++++++++++++++++++++++++++++*)
(* Handshake with the terminal or terminal emulation *)
ComControl(
COMin:=KL6InData ,
COMout:=KL6OutData ,
TxBuffer:=TxBuffer ,
RxBuffer:=RxBuffer );
(*-------------------------------- TRANSMISSION --------------------------------------*)
Timer1(IN:=NOT Timer1.Q,PT:=t#100ms); (* a protocol is transmitted *)
(* every 0.5 seconds *)
IF Timer1.Q THEN
Starten:=TRUE;
END_IF
IF Starten THEN
(*------------------------- calculate CHECKSUM --------------------------------------*)
Summe:=0;