RsFlipFlop Function Block

The Rs Flip Flop function block prioritizes the reset input if both the inputs are "true". Rs Flip Flop has a one-bit functional block.

Rs Flip Flop function block has two inputs:

The RS abbreviation stands for Set or Reset. The flip-flop is reset to its original state using the Reset input, and the output is either logic level "1" or logic level "0". It is determined by the flip-Set flop's or Reset condition. The term "flip flop" refers to the ability to be "FLIPPED" into one logic state and "FLOPPED" back into another.

The basic NOR gate and RS Flip Flop circuit are used to store the data and thus provide feedback from both of its outputs again back to its inputs.

The RSFlipFlop has three inputs Set, Reset, and Out (current output ) that relate to its current state.

Figure 1: RsFlipFlop - Function Block

Figure 2: RsFlipFlop - Property Sheet

Inputs with value "false" or "null" are not evaluated. The output keeps on last value.

Figure 3: RsFlipFlop - Logic Diagram

Input

Input Name

Description

Set

This is a boolean point input slot.

Reset

This is a boolean point input slot. If both inputs are "true", it has a priority.

Table 1:Inputs of RsFlipFlop Function

Output

Output Name

Description

Out

Output = "true" or "false" based on the input and reset value.

Table 2:Output of RsFlipFlop Function

Parameter

Parameter Name

Description

Out Save

Master Sync Enabled : If you set it to "true" the last output will be set as output for one cycle after the controller restarts. The application can use it to return to the same state before the controller restart.

Out: To enable or disable the Out feature.

Table 3:Parameter of RsFlipFlop Function

Truth table

Set

Reset

Output

false

false

No change or remains in previous state.

false

true

false

true

false

true

true

true

false

Table 4:Truth table of RsFlipFlop Function

Example

All the five conditions.

1.       If Set and Reset are "true", Out is "false".

Figure 4: Set and Reset "true", Out "false".

2.       Set and Reset are set to "false", Out will be retained the last state.

Figure 5: Set and Reset "false", Out last state.

3.       If Set = "true"; Reset = "false", Out = "true".

Figure 6: Set "true", Reset "false" and Out = "false".

4.       If Set = "false" and Reset = "true", Out = "false".

Figure 7: Set "false", Reset "true" and Out "false".

Refer to General Description for general information about IRMN4 Function Blocks.