1- Bit Instructions
2- Timer and Counter Instructions
3- Compare Instructions
4- Compute/Math Instructions
5- Move/Logical Instruction
6- Program Control Instructions
7- Select/Limit Instructions
8-Totalizer, PIDE, Ramp/Soak

Section-7:Select/Limit Instructions

Use this instruction:

  1. SEL
  2. ESEL
  3. SSUM
  4. SNEG
  5. MUX
  6. HLL
  7. RLIM

If you want to:

  • Select
  • Enhanced Select
  • Selected Summer
  • Selectable Negate
  • Multiplexer
  • High/Low Limit
  • Rate Limiter

Select (SEL)

The SEL instruction uses a digital input to select one of two inputs.

Input Parameter

  1. In1
  2. In2
  3. Selector In

 Output Parameter

  1. OUT

Description

  • The first analog signal input to the instruction.          Valid =any float    Default =0.0
  • The second analog signal input to the instruction.    Valid = any float     Default =0.0
  • The input that seletcts between In1 In2 .     Default is Cleared.

Description

  • The calculated output of the algorithm.Arithmetic status flags are set for this output

Example:

The SEL instruction selects In1 or In2 based on SelectorIn . If SelectorIn is set, the instruction sets out = in2. If SelectorIn is Cleared, the instruction sets out = In1. 

Enhanced Select (ESEL)

The ESEL instruction lets you select one of as many as six input. Selector options include :

  • manual select (either by operator o by program)
  • high select 
  • low select 
  • median select
  • average (mean) select

Input Parameter

  1. In1
  2. In2
  3. In3
  4. In4
  5. In5
  6. In6
  7. Selector Mode

Description

  • The first analog signal input to the instruction.          Valid =any float    Default =0.0
  • The second analog signal input to the instruction.    Valid = any float     Default =0.0
  • The third analog signal input to the instruction.          Valid = any float     Default = 0.0
  • The fourth analog singnal input to the instruction.     Valid = any float     Default = 0.0
  • The fifth analog signal input to the instruction.           Valid = any float     Default = 0.0
  • The sixth analog signal input to the instruction.          Valid = any float     Default = 0.0
  • Selector mode input. This value determines the action of the instruction.

Value                                                     Description

  1.                                                                  manual               
  2.                                                                  high select
  3.                                                                   low select
  4.                                                                  median select
  5.                                                                  average select

If this value is invalid, the instruction sets the appropriate bit in status and does not updete out.            Valid = o to 4                         Default =0

Output Parameter:

  1. Out
  2. SelectedIn
  3. ProgOper
  4. Override

Description:

  • The calculated output of the algorithm. Arithmetic status flags are set for this output.
  • Number of input selected. The instruction uses this value to display the number of the input currently being placed into the output. If the selector mode is average select, the instruction sets SelectedIn = 0.
  •  Program/Operator control indicator. Set when in Program control. Cleared when in Operator control.
  • Override mode. Set when the instruction is in Override mode

Example

This ESEL instruction selects In1, In2, or In3,based on the SelectorMode. In this example, Selectormode = 1, Which means high select.The insturction determines which input value is the greatest and sets Out = greatest In

Selected Summer (SSUM)

The SSUM instruction uses Boolean inputs to select real inputs to be algebraically summed.

Input Parameter

  1. In1
  2. Select1
  3. In2
  4. Select2
  5. In3
  6. Select3
  7. In4
  8. Select4

Description

  • The first input to be summed.               Valid = any float                 Default = 0.0
  • Selector signal for the first input.          Default is Cleared.
  • The Second input to be summed.         Valid = any float                 Default = 0.0
  • Selector signal for the second input     Default is cleared.
  • The third input to be summed.               Valid = any float                Default = 0.0
  • Selector signal for the third input.          Default is cleared.
  • The fourth input to be summed.             Valid = any float                Default = 0.0
  • Selector signal for the fourth input.        Default is cleared.

                                      

Output Parameter:

  1. Out

Description:

  • The calculated output of the algorithm.Arithmetic status flags are set for this ouput.,

Example

The value of select 2 determine whether to select analogInput1 and analog_input2, respectively. The instruction then adds the selected inputs and places the result in Out. 

Selectable Negate (SNEG)

The SNEG instruction uses a digital input to select between the input value and negative of the input value.

Input Parameter

  1. In 
  2. NegateEnable

Description

  • The analog signal input to the instruction.         Valid = any float                 Default = 0.0
  • Negate enable. When NegateEnable is set, the instruction sets Out to the negative value of In.                   Default is set.

Output Parameter:

  1. Out

Description:

  • The calculated output of the algorithm.Arithmetic status flags are set for this ouput.,

Example

The output   determines whether to negate In or not. The instruction  sets out = In if NegateEnable is set. Out becomes an input parameter

Multiplexer (MUX)

The MUX instruction selects one of eight inputs based on the selector input.

Input Parameter

  1. In1
  2. In2
  3. In3
  4. In4
  5. In5
  6. In6
  7. In7
  8. In8
  9. Selector

Description

  • The first analog signal input to the instruction.                             Valid = any float               Default = 0.0
  • The second analog signal input to the instruction.                       Valid = any float               Default = 0.0
  •  The third analog signal input to the instruction.                           Valid = any float               Default = 0.0
  •  The fourth analog signal input to the instruction.                         Valid = any float              Default = 0.0
  •  The fifth analog signal input to the instruction.                             Valid = any float              Default = 0.0
  •  The sixth analog signal input to the instruction.                            Valid = any float              Default = 0.0
  •  The seventh analog signal input to the instruction.                       Valid = any float             Default = 0.0
  •  The eighth analog signal input to the instruction.                          Valid = any float              Default = 0.0
  •  The selector input to the instruction. This input determines which of the inputs (1-8) is moved into Out. If this value is invalid (which includes 0), the instruction sets the appropriate bit in Status and holds Out at its current value.                                 Valid = 1 to 8               Default = 0

Output Parameter:

  1. Out

Description:

  • The selector output of the algorithm. Arithmetic status flags are set for this output.

Example

This MUX instruction selects In1, In2, In3, based on the Selector. The instruction sets Out = In  which becomes an input an parameter for example , if value = 2, the instruction sets Out = analog _input2. 

High / Low Limit (HLL)

The HLL instruction limits an analog input between two values. You can Select high/low,high,or low limits.

Input Parameter

  1. In1

Description

  • The analog signal input to the instruction.          Valid = any float         Default = 0.0

Output Parameter:

  1. Out
  2. High Alarm
  3. Low Alarm 

Description:

  • The calculated output of the algorithm. Arithmetic status flags are set for this output.
  • The high alarm indicator. Set when In >= HighLimit. 
  • The low alarm indicator. Set when In <= LowLimit

Example

This HLL instruction llimits In between two values and sets HighAlarm or LowAlarm, needed when In is outside the limits. The instruction sets Out = limited value of In, which becomes an input parameter for function_block_C.

Rate Limiter (RLIM)

The RLIM instruction limits the amount of change of a signal over time.

Input Parameter

  1. In1
  2. By Pass

Description

  • The analog signal input to the instruction.          Valid = any float         Default = 0.0
  • Request to bypass the algorithm.when set, Out = In.           Default is cleared.

Output Parameter:

  1. Out

Description:

  • The calculated output of the algorithm. Arithmetic status flags are set for this output.

Example

The RLIM instruction limit In by IncRate . If analog_input1 changes at a rate greater than the IncRate value, the instruction limits In. The instruction sets Out = rate limited value of In, which becomes an input parameter for function_block_C. 

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