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CTUD / CTUD_S

CTUD_S

Type	Function block Available as standard (non-safety-related) and safety-related type (*_S). For the safety-related type, the safety-related data types (SAFE*) are expected at the formal parameters.
Description	Counts up or down. In case of a rising edge at the input CU, CV is increased by one. In case of a rising edge at the input CD, CV is decreased by one. If CV = PV, QU is set to TRUE. If CV = 0, QD is set to TRUE. If RESET = TRUE, the counter is initialized to 0. If LOAD = TRUE, the counter is initialized to PV. To enable counting, RESET and LOAD must be FALSE. Otherwise the counter will always be re-initialized.
Notes	The inputs CU, CD, RESET, LOAD and the outputs QU and QD can be negated. Note: The negation of formal parameters is not supported in safety-related code (SNOLD). Function blocks have to be instantiated. The instance name of the function block has to be declared in the 'Variables' table of the POU where the FB is going to be used. The instance name must be unique within the POU.
Parameters	Inputs CU Data type: (SAFE)BOOL Description: If a rising edge is detected, CV is increased by one. CD Data type: (SAFE)BOOL Description: If a rising edge is detected, CV is decreased by one. RESET Data type: (SAFE)BOOL Description: If TRUE, the counter is initialized with 0. If FALSE, counting is enabled. LOAD Data type: (SAFE)BOOL Description: If TRUE, the counter is initialized with PV. If FALSE, counting is enabled. PV Data type: (SAFE)INT Description: Preset value. Outputs QU Data type: (SAFE)BOOL Description: TRUE if CV = PV. QD Data type: (SAFE)BOOL Description: TRUE if CV = 0. CV Data type: (SAFE)INT Description: Counter result.