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How relay got energized?
Q1)How the Internal Relay Coil is energized by Up & Down Counter viz. CTU & CTD even in the initial state when neither XUp  nor              XDown is Pressed or say their initial states are 0?

Q2)Can we compare an Instruction with a constant or variable in any of the compare or such kind of instruction, such as been done              with CCounter? I want to mean that CCounter is an Instruction whereas Counter is the name given to it, so, can we directly                      compare some variable or constant of an instruction (say compare instruction's 0 (constant)) with another instruction (I am not                saying variable or constant of the second instruction, I am saying the instruction itself, say CCount) directly, as being shown in the          tutorial?

OpenPLC-with-LDmicro CTD-Counter 05-06 min 20-30 sec 11-06-22, 12:41 p.m. sc256356


1) The Rrelay is energized since both the CTU and CTD conditions are true if the Ccount value is greater than or equal to 0.The output condition from the counter is true if the counter condition is satisfied, and false otherwise. The rung output condition may be true even if the input condition is false; it only depends on the counter variable.

You can refer to the Manual of LDmicro which is available in the LDmicro interface under 'Help', when you are confused with the working of any instruction.

2) Instructions like timers and counters have a variable associated with it. The variable when satisfies the condition given in the respective timer/counter, the timer/counter will output true.

15-06-22, 3:38 p.m. NirmalaVenkat

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