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Reading and Writing

Use a PLC or Block Tag for reading or writing Words (16-bit values) at the memory address specified by the N3/B3 parameter, according to the type of variable selected by the N1/B1 parameter.

For Data Module-type variables, with the N1/B1 parameter equal to 68, it is also necessary to indicate the DB Number using the N2/B2 parameter of the PLC or Block Tag.

Parameters for reading and writing Memory Variables

 

To manipulate an individual position of a bit in a 16-bit register, add the value 256 to the type of variable defined by the N1/B1 parameter and specify the bit position via the N4/B4 parameter.

For example, to access the bit 5 (five) of a Merker variable, define the N1/B1 parameter with the value 77 + 256, that is, N1/B1 equal to 333 and specify the N4/B4 parameter with the value 5 (five) to determine the respective position of that bit.

 

Reading or writing bits using PLC Tags

The N4 parameter must be defined with values from 1 (one) to 16, according to the next table.

 

 

Reading bits using Block Tags

When using Block Tags, each Element of a Block Tag represents the position of a Word bit, as shown on the next table.

 

 

Users can also access bits from multiple Word values, by adding more Elements to a Block Tag, according to the next tables.

 

 

 

If users want to access a group of bits in a Word value, they must use the B4 parameter as the start bit. In the example of the next table, the bits from 8 (eight) to 15 of a Word are accessed using a Block Tag with 8 (eight) Elements and its B4 parameter equal to 9 (nine).