Conditional formatting?

[an]

Hello!

Is it possible conditionaly to obstruct to write data in
cell?
For example:

=IF(A2<A1;"ERR";A2)
(this is circular cell)

Thanks in advance.
an

 

[icestationzbra]

use data validation to allow entry of data in a cell only if it conform
to certain conditions.

go over to Data - Validation. from the Allow list, select Whole Numbe
(or Decimal). from the Data section, select Greater Than or Less Than
in the resulting Minimum or Maximum section, enter either a value or
cell address. you can also provide a comprehendible error message i
the Error Alert tab

 

[an]

Ok.

Many thanks for yout help.
an