Chapter 8. Communication Function
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(4) Program description
z It saves 16#FF (or 255) at %MW0 (It is coincided with %MX0 ~ %MX15 or %MB0 ~ %MB1) in function block
MOD0506 (function code 06). It then reads %MX0 through MOD0102 (function code 01), and again saves 0
at %MX0 ~ %MX9 using function block MOD1516 (function code 15), and then reads %MW0 through Mod0304.
z 8 LEDs of output contact points operate on/off continually.
z The above figure is the monitored scene of the program operation. Therefore the values appeared in _RD_DB,
_RD_DW, array variables are not the initial ones, but the resulted value after executing reading.
z Variables like instance name NDR, Instance name ERR, Instance name STATUS are automatically generated
when an instance variable of function block is declared.
z _1ON flag is a flag that is on for 1 scan.
z Previous function blocks’ NDR output is the input condition for REQ of each function block.
z The size of _BYTE_CNT must be the same when it is converted into bytes.
z An error occurs when the size of array variable is smaller than the data to be read or to be written.
z Table of variables
Variable Variable type Initial value Variable Variable type Initial value
_SLV_ADDR USINT 17(16#11) _NH0102 USINT 0(16#00)
_FUNC0102 USINT 1(16#01) _NH0304 USINT 0(16#00)
_FUNC0304 USINT 3(16#03) _NH0506 USINT 0(16#00)
_FUNC0506 USINT 6(16#06) _NH1516 USINT 0(16#00)
_FUNC1516 USINT 15(16#0F) _NL0102 USINT 1(16#01)
_AH0102 USINT 0(16#00) _NL0304 USINT 255(16#FF)
_AH0304 USINT 0(16#00) _NL0506 USINT 255(16#FF)
_AH0506 USINT 0(16#00) _NL1516 USINT 10(16#0A)
_AH1516 USINT 0(16#00) _RD_DB BOOL-typed ARRAY [40] {0,0,…,0}
_AL0102 USINT 0(16#00) _RD_DW WORD-typed ARRAY [4] {0,0,0,0}
_AL0304 USINT 0(16#00) _WR_DBW
BYTE-typed ARRAY [4] {0,0,0,0}
_AL0506 USINT 0(16#00) _BYTE_CNT
USINT 2(16#02)
_AL1516 USINT 0(16#00)