GE GFK-1004B user manual +ÐÐ Ððððð ÐÐÐ+BLKMV+Ð INT

4

<< RUNG 5 >>
HEALTHY READREQ		+ÐÐÐб+
+ÐÐ] [ÐÐÐÐÐ] [ÐÐÐ+BLKMV+Ð
		INT
	CONST Ð+IN1 Q+Ð%R00322
	+00000
	CONST Ð+IN2
	+00001
	CONST Ð+IN3
	+00000
	CONST Ð+IN4
	+00000
	CONST Ð+IN5
	+00000
	CONST Ð+IN6
	+00000
	CONST Ð+IN7
	+00000	+ÐÐÐÐÐ+
<< RUNG 6 >>
HEALTHY READREQ		+ÐÐÐÐÐ+
+ÐÐ] [ÐÐÐÐÐ] [ÐÐÐ+COMM_+Ð
		REQ
			CMRQFLT
	%R00301Ð+IN FT+ÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐÈÐÐÐÐÐÐÐ(S)
	CONST
	0004Ð+SYSID
	CONST Ð+TASK
	00000000	+ÐÐÐÐÐ+

Rung # 1: Input LANIFOK (bit 16 of the LAN Interface Status bits) monitors the health of the Ethernet Interface. If it is OK to send a COMMREQ, the HEALTHY coil is ON. HEALTHY is used as an interlock for Rungs 3-6.

Rung # 2: Input BEGREAD triggers READREQ, which enables execution of the MOVE and COMMREQ functions. READREQ is a one-shot coil, activating once when BE- GREAD transitions from OFF to ON.

Rung # 3: The MOVEWORD function moves a zero to the CRS word referenced in the Command Block (see rung #4). This clears the CRS word. This rung also resets the FT output coil of the COMMREQ Function Block in rung #6.

It is vital that the CRS Status Word be cleared and the COMMREQ fault output coil be cleared each time before initiating a COMMREQ function.

Rungs # 4-5: The BLKMVINT functions set up the COMMREQ Command Block con- tents. When these rungs are activated, the constant operands are moved into the memory beginning at the address indicated in the instruction. The constant operands in this example are defined in the Establish Read Channel Example in Section 3 of this chapter.

Rung # 6: The COMMREQ Function Block has 3 input parameters and two output pa- rameters.

HThe IN field points to the starting location of the Command Block parameters (%R00301 in this example).

4-36 TCP/IP Ethernet Communications User's Manual ± January 1996 GFK-1004B