Up Counter Instruction In PLC

Up Counter Description :

• Count Up Instruction Use to Increment the Value at Output CV.

• Count Up Input Changes from 0 to 1 (Positive Signal Edge) Current Counter Value Increment at Output CV.
• Counter Value Increment Each Time When Positive Signal Edge Is Detected.
• When Counter High Limit Reached, the Signal State at the CU Input no longer effect on the Count up Instruction.
• Current Counter Value is Greater than or Equal to the Value of the PV Parameter the Output Q is set to Signal State 1.
• When the Signal State at Input R Changes from 0 to 1 the Value at CV Output is Reset to Zero. 

Up Counter Parameters :

Parameter	Declaration	Data type	Description
CU	Input	BOOL	Count input
R	Input	BOOL	Reset input
PV	Input	Integers	Value at which the output Q is set.
Q	Output	BOOL	Counter status
CV	Output	Integers, CHAR, WCHAR, DATE	Current counter value

Up Counter Example :

Up Counter

• When the Signal State of the TAG_1 Changes From 0 to 1, the Count Up Instruction is executed at and the Current Counter Value of the CV Value is Incremented by one.
• Counter Value is Incremented until the High Limit of the Specified Data Type (INT= 32768) is Reached.
• When Current Counter Value is Greater than or equal to Zero the value of the PV Value Output Tag_3 Signal State 1.
• In all other cases, the Output TAG_3 has Signal State 0.
• When the Signal State at Input TAG_2 Changes from 0 to 1 the Value at CV Output is Reset to Zero.

Timer Off Delay (TOF) Timer Description

TOF Timer Description :

• TOF Timer instruction to set Time Delay resetting of the output by set PT Time of Timer. 
•  Input Changes From 0 to 1 (positive signal edge) Timer PT time Start and Output change from 0 to 1 (ON).
•  When PT Time Equal to Elapsed Time Output Change From 1 to 0 (Output OFF).
• Output Remain On as long as PT Time Running.
• When PT Time Expire Output change from 1 to 0 (Output OFF).

TOF Timer Parameters :

Parameters	Declaration	Description
IN	Input	Start input
PT	Input	Duration of the off delay
Q	Output	Output that is reset when the time PT expires
ET	Output	Current time value

TOF Timer Timing Diagram :

TOF Timer

TOF Timer Example :

• Start PB change from 0 to 1,TOF Timer Preset Time Start.
• When Start PB Changes from 0 to 1 Output Change from 0 to 1 (Motor ON).
• When PT Time Completed Motor Changes From 1 to 0 (Motor OFF).
• Motor set to on as long as PT Time Running.