Hi everyone

in the s7-1200 manual (page 90) it said whenever the operation mode changes from stop to run the CPU clears the process image inputs initializes the process image output and process the startup OBs any read access to the process image inputs by instructions in the startup will be read zero rather than the current physical inputs value so I have put the network in the startup Ob100 which mean  I performed the read access to the input process image so according to what was mentioned the Q output will never be on but it turns on when I goes from stop to run mode

But also in the previous page it is mentioned that the CPU and the startup mode copies the state of the physical inputs to the I memory this is mentioned in page 89

What am I missing

Kind regards

adamlahadi

Hi everyone

in the s7-1200 manual (page 90) it said whenever the operation mode changes from stop to run the CPU clears the process image inputs initializes the process image output and process the startup OBs any read access to the process image inputs by instructions in the startup will be read zero rather than the current physical inputs value so I have put the network in the startup Ob100 which mean  I performed the read access to the input process image so according to what was mentioned the Q output will never be on but it turns on when I goes from stop to run mode

But also in the previous page it is mentioned that the CPU and the startup mode copies the state of the physical inputs to the I memory this is mentioned in page 89

What am I missing

Kind regards

 

the manual you have is not the the one i have as page 90 is not with the information about the plc starting which tells about the plc buffer memories cleared before the sequencing of normal action is taking place where the inputs and outputs swap between actual and internal memory which we call in addresses like %I0.0 and %Q0.0 that can be called with the :P sign at the back in case of processing the instructions inside interrupts but also for ob100 which is what the documentation was talking about    

image is shown above for you to show what was your question

But in the red highlights sentence in the "D"the CPU copies the states of the physical inputs to the I memory I think there is a contradiction in this

qwazee

 

adamlahadi

Hi everyone

in the s7-1200 manual (page 90) it said whenever the operation mode changes from stop to run the CPU clears the process image inputs initializes the process image output and process the startup OBs any read access to the process image inputs by instructions in the startup will be read zero rather than the current physical inputs value so I have put the network in the startup Ob100 which mean  I performed the read access to the input process image so according to what was mentioned the Q output will never be on but it turns on when I goes from stop to run mode

But also in the previous page it is mentioned that the CPU and the startup mode copies the state of the physical inputs to the I memory this is mentioned in page 89

What am I missing

Kind regards

 

the manual you have is not the the one i have as page 90 is not with the information about the plc starting which tells about the plc buffer memories cleared before the sequencing of normal action is taking place where the inputs and outputs swap between actual and internal memory which we call in addresses like %I0.0 and %Q0.0 that can be called with the :P sign at the back in case of processing the instructions inside interrupts but also for ob100 which is what the documentation was talking about    

image is shown above for you to show what was your question

you keep it a secret which manual you use it is the one from 2016 best to get the the manual that is same as the PLC firmware being used can be loaded from the SiePortal allows to make complaint about inaccuracy of the manual on the page

Import of a technical question via PM from the user adamlahadi.

ln ths s7-1200 firmware V4.2 manual page 89 it's mentiond that in the startup process the CPU copies the state of the physical inputs to the I memory,in page 90 under startup processing it said the opposite of that

so in the startup ob100 i put (NO i0.0) to set Q0.0 ,so as a resault and before the CPU goes to run mode the Q0.0=1, so we can say that what was mentioned in page 89 (D) was true not page 90 which tells you that (for my case ) that i need to perform an immediat addressing in order to set the Q0.0

(NO I0.0:p) to set Q0.0

i found a contradiction between the two pages 89/90 or it's a miss understanding from me

can you help with that

kind regards