Specifications

8.3
Address structure
8
-5
8.3.3 Addressing of input, output, bit memory, and data bits
Each bit is identified by the address of a byte to which it belongs and its own address relative
to that byte (each byte consists of 8 bits). Thus a bit is expressed in the following format:
[address symbol][byte address]. [bit address] (e.g., I1.2)
 Address symbol
A bit address starts with a symbol such as I, Q, M, or DBX.
The symbol for a data bit is DBX (e.g., DBX1.2).
 Bit address
The bit address part of a bit address is the numerical part after the period (.). It is repre-
sented by a digit between 0 and 7 (the 8 bits make up a byte).
 Byte address
The byte address part of a bit address is the numerical part after the address symbol and
before the period (.). It is represented by an integer in the decimal notation (0, 1, 2, 3, 4, 5,
6, 7, 8, 9, 10, 11, ...). As a byte is expressed as a combination of an address symbol and a
byte address, I1.2 and Q1.2 are two different bits.
8.3.4 Addressing of timers and counters
A timer or counter is expressed as a combination of an address symbol and a byte address
(with no bit address). Thus a timer or counter is expressed in the following format:
[address symbol][number] (e.g., T10)
The number is any integer in the decimal notation (starting with 0). The maximum allow-
able value of the number depends on the CPU used.