# Memory size for external variables (P-STUP-00037)

P-STUP-00037 | Memory size for external variables
Description | This parameter dimensions the memory area available for the external variables of each channel on the HLI. A separate memory area of this size is created for global external variables. The number defined here determines the number of 24-byte blocks of which each of these V.E. memory areas consists.
Parameter | ext_var_max
Data type | UNS16
Data range | 0 ... MAX(UNS16)
Dimension | ----
Default value | 0
Remarks | This parameter is used automatically in TwinCAT systems.