SUB

The IEC operator subtracts variables.

Allowed data types: BYTE, WORD, DWORD, LWORD, SINT, USINT, INT, UINT, DINT, UDINT, LINT, ULINT, REAL, LREAL, TIME, TIME_OF_DAY, TOD, LTIME, LTIME_OF_DAY, LTOD, DATE, DATE_AND_TIME, DT, LDATE, LDATE_AND_TIME, LDT

Possible combinations for time data types:

• TIME  - TIME   = TIME
• LTIME - LTIME  = LTIME

Possible combinations for date and time data types:

• DATE  - DATE   = TIME
• LDATE - LDATE  = LTIME
• TOD   - TIME   = TOD
• LTOD  - LTIME  = LTOD
• TOD   - TOD    = TIME
• LTOD  - LTOD   = LTIME
• DT    - TIME   = DT
• LDT   - LTIME  = LDT
• DT    - DT     = TIME
• LDT   - LDT    = LTIME

Negative TIME/LTIME values are undefined.

Samples:

ST:

nVar := 7-2; 

FBD: