How 27648 Analaog Maximum Value ?

Nurmard

Hello,

Good time to all my friends, can someone guide me on what reasoning was used to select the number 27648 in the analog inputs?

For example, regarding the highest value of the counters, we know that the memory architecture is the left four bits unused and the next 12 bits  can count up to 999 as 3 BCD nibbles, but I did not find a logical reason  for this number (27648).

I will be happy to help you.

Best Regards 

Navid

 Hello,

First, I just wanted to highlight that the analog values are represented in 16-bit memory size. Its data type is INT and not WORD.

Both Integer and WORD can be represented in 16-bit but there is a difference in the data structure between them. 

The Word (16-bit size) has a bits from No. 0 to No-15

Bit No. 15 is dedicated for sign

• Max. Positive No. for INT = 0111 1111 1111 1111 (Bin) = 32767 (Dec) 

And as per 2nd post from dchartier here, see the attached picture,

• The value 32767 dec is equivalent to max. value of overflow range.
  And Overflow range is between 32512 & 32767 dec (>99% & 100%)
• The value 32511 dec is equivalent to max. value of over-range
  And over range is between 27649 & 32511 dec (>85% - 99%)
• Rated value is between 0 & 27648. (0-85%)

For a better understanding of different data types, see Section 23.3, For INT data type see section 23.3.2.1 of the following manual SIMATIC Programming with STEP 7