Sotu And Sotd (Single Output Up And Down) - IDEC FC4A-C10R2 User Manual

7: B I
ASIC NSTRUCTIONS
SOTU and SOTD
The SOTU instruction "looks for" the transition of a given input from off to on. The SOTD instruction looks for the transi-
tion of a given input from on to off. When this transition occurs, the desired output will turn on for the length of one scan.
The SOTU or SOTD instruction converts an input signal to a "one-shot" pulse signal.
A total of 512 (all-in-one 10-I/O type CPU module) or 3072 (other CPU modules) SOTU and SOTD instructions can be
used in a user program.
If operation is started while the given input is already on, the SOTU output will not turn on. The transition from off to on is
what triggers the SOTU instruction.
When a relay of the CPU or relay output module is defined as the SOTU or SOTD output, it may not operate if the scan
time is not compatible with relay requirements.
Ladder Diagram
SOTU
I0 Q0
SOTD
I0 Q1
Timing Chart
ON
Input I0
OFF
ON
Output Q0
OFF
ON
Output Q1
OFF
Note: "T" equals one scan time (one-shot pulse).
There is a special case when the SOTU and SOTD instructions are used between the MCS and MCR instructions (which
are detailed on page 7-23). If input I2 to the SOTU instruction turns on while input I1 to the MCS instruction is on, then
the SOTU output turns on. If input I2 to the SOTD instruction turns off while input I1 is on, then the SOTD output turns
on. If input I1 turns on while input I2 is on, then the SOTU output turns on. However, if input I1 turns off while input I2 is
on, then the SOTD output does not turn on as shown below.
Ladder Diagram
MCS
I1
SOTU
I2 M1
SOTD
I2 M2
MCR
7-22
(Single Output Up and Down)
Program List
Instruction
LOD
SOTU
OUT
LOD
SOTD
OUT
T
T T
Timing Chart
Input I1
Input I2
SOTU Output M1
SOTD Output M2
« FC4A M
Data
Caution
I0
• For restrictions on ladder programming of
Q0
SOTU and SOTD instructions, see page 29-22.
I0
Q1
T
ON
OFF
ON
OFF
ON
OFF
ON
OFF
S U ' M
ICRO MART SER S ANUAL
No Output No Output
»