29: TROUBLESHOOTING
29-22 « FC4A MICROSMART USER’S MANUAL »
Restriction on Ladder Programming
Due to the structure of WindLDR, the following ladder diagram cannot be programmed — a closed circuit block is formed
by vertical lines, except for right and left power rails, and the closed circuit block contains one or more prohibited instruc-
tions shown in the table below.
The error detection depends on the version of WindLDR. When using WindLDR ver. 4.4 or earlier, particular care is needed.
Modifying Prohibited Ladder Programs
Intended operation can be performed by modifying the prohibited ladder program as shown in the examples below:
Prohibited Instructions OUT, OUTN, SET, RST, TML, TIM, TMH, TMS, CNT, CDP, CUD, SFR, SFRN, SOTU, SOTD
Error
Detection
WindLDR
Ver. 4.4 or earlier
The ladder program is converted to incorrect mnemonics, without showing an error
message. The program can be downloaded to the CPU module, causing an unexpected
operation and possible danger.
WindLDR
Ver. 4.5 or later
When converting the ladder program, an error message is shown, such as “TIM fol-
lows an invalid operand.” Conversion fails to create mnemonics and the program is
not downloaded to the CPU module.