Chapter 4. Ladder Diagram (LD) Programming200 PACSystems* RX7i, RX3i and RSTi-EP CPU Programmer's Reference Manual GFK-2950C4.10.8 SubtractWhen the SUB function receives power flow, it subtracts the operandIN2 from the operand IN1 of the same data type as IN2 and stores theresult in the output variable assigned to Q, also of the same data type.Mnemonics:SUB_DINTSUB_INTSUB_REALSUB_LREALSUB_UINTThe power flow output is energized when SUB is performed, unless an invalid operation or Overflowoccurs. (For more information, refer to the section on Overflow.)If a SUB_UINT operation results in a negative number, Q wraps around, yielding a result that is thehighest possible value (65535) minus the absolute value of the difference -1.The following REAL and LREAL operations are invalid for SUB:▪ (± ∞) – (± ∞)▪ I1 and/or I2 is NaN (Not a Number)Mnemonic Operation Displays asSUB_INT Q(16-bit) = IN1(16-bit) – IN2(16-bit)base 10 number with sign, up to 5 digits longSUB_DINT Q(32-bit) = IN1(32-bit) – IN2(32-bit)base 10 number with sign, up to 10 digits longSUB_REAL Q(32-bit) = IN1(32-bit) – IN2(32-bit)base 10 number, sign and decimals, up to 8 digits long(excluding the decimals)SUB_LREAL Q(64-bit) = IN1(64-bit) – IN2(64-bit)base 10 number, sign and decimals, up to 17 digits long(excluding the decimals)SUB_UINT Q(16-bit) = IN1(16-bit) – IN2(16-bit)base 10 number, unsigned, up to 5 digits longOperands for SubtractParameter Description Allowed Operands OptionalIN1 The value to subtract from; the value to the left of the minussign (-) in the equation IN1-IN2=Q.All except S, SA, SB, SC NoIN2 The value to subtract from IN1; the value to the right of theminus sign (-) in the equation IN1-IN2=Q.All except S, SA, SB, SC NoQ The result of IN1-IN2. If a SUB operation on signed operandsresults in underflow, Q is set to the smallest possible valueand there is no power flow.If a SUB_UINT operation results in Overflow, Q wraps around.For example,The SUB_UINT operation 600 – 601 = –1 sets Q to 65535The SUB_UINT operation 600 – 602 = –2 sets Q to 65534All except S, SA, SB, SCand constantNo
