First out Bit in Siemens SCL

Hello all,

I want to do it first out bit detection in 16 bits per group and could somebody provide me samples? i prefer SCL and STL is ok for me too. appreciate help in advance.

Can you give an example 16 bits and what you are looking to detect?

First out = First bit that is zero - returns bit number?

Thanks for asking..

Hi LD,

Yes " First out = First bit that is zero - returns bit number? "

Details: I want to Latch out only one bit depend on input trigger bit (1 = normal, 0 = Alarm) positions. for example, i have AlarmIn_1..16 and if AlarmIn_9 trigger first then QAL_IN9 need to latch true until reset by operator. i think this is the better idea to detect which bit is trigger first in 16. thanks in advance.

VAR_OUTPUT
QAL_IN1 { S7_m_c := 'true' } : BOOL ;
QAL_IN2 { S7_m_c := 'true' } : BOOL ;
QAL_IN3 { S7_m_c := 'true' } : BOOL ;
QAL_IN4 { S7_m_c := 'true' } : BOOL ;
QAL_IN5 { S7_m_c := 'true' } : BOOL ;
QAL_IN6 { S7_m_c := 'true' } : BOOL ;
QAL_IN7 { S7_m_c := 'true' } : BOOL ;
QAL_IN8 { S7_m_c := 'true' } : BOOL ;
QAL_IN9 { S7_m_c := 'true' } : BOOL ;
QAL_IN10 { S7_m_c := 'true' } : BOOL ;
QAL_IN11 { S7_m_c := 'true' } : BOOL ;
QAL_IN12 { S7_m_c := 'true' } : BOOL ;
QAL_IN13 { S7_m_c := 'true' } : BOOL ;
QAL_IN14 { S7_m_c := 'true' } : BOOL ;
QAL_IN15 { S7_m_c := 'true' } : BOOL ;
QAL_IN16 { S7_m_c := 'true' } : BOOL ;
END_VAR

Which platform is this for - S7 classic or TIA portal?

S7 classic

I am using S7 classic + WinCC.

Example tested using PLCSIM:

it's perfect!!!

Thanks for nice example . i tested and it's perfect coding. but one thing, QOUT should allow reset/Scan only when all inputs are back to normal condition. i will study ur code and modify it.