Nexto XF #59 – Using the RAMP_REAL Functional Block

The purpose of this tutorial is to explain how to insert and use the RAMP_REAL functional block in a MasterTool X project.

Components

Equipment: 1 computer/laptop.

Software:  MasterTool X

Tutorial Sections

1. ARCHITECTURE
2. DEVELOPMENT

1.ARCHITECTURE

A computer/laptop is required to use MasterTool X.

Figure 1. Computer running MasterTool X

2.DEVELOPMENT

The RAMP_REAL block is used to limit the variation of a value over time, controlling the rise (ascending) and fall (descending) speed of a signal.

It is very useful when you want to avoid abrupt changes in variables, ensuring a smoother transition.

This block is widely applied in:

• Speed control
• Motor soft start
• Gradual setpoint adjustment
• Smoothing of analog signals

Prerequisite

The RAMP_REAL block is only available in the Util library.

Therefore, the library must be added to the project through the Library Manager.

Functionality

The RAMP_REAL block limits the speed at which the output value follows the input, controlling:

• How much the value can rise per time interval
• How much the value can fall per time interval

Unlike the RAMP_INT, the only difference is the data type, which in this case is REAL.

The block works as follows:

• If the input value increases rapidly, the output rises in a limited way according to ASCEND
• If the input value decreases rapidly, the output falls in a limited way according to DESCEND
• The variation occurs over the time defined in TIMEBASE

Inserting the block into the logic

The block does not appear directly in the toolbox, so it must be inserted manually:

1. Create a new network
2. Insert a generic box (EN/ENO)
3. Inside the box, type:
   RAMP_REAL

Figure 2. Adding the RAMP_REAL Functional Block

Input Parameters

IN (REAL)

• Input value of the function

ASCEND (REAL)

• Maximum allowed rise value per time interval

DESCEND (REAL)

• Maximum allowed fall value per time interval

TIMEBASE (TIME)

• Defines the time interval for applying the rise and fall rates

RESET (BOOL)

• Resets the block

Output

OUT (REAL)

• Resulting value after applying the ramp limitation

 RESET Behavior

• When RESET = TRUE, the ramp is interrupted
• The last output value (OUT) is held
• When RESET returns to FALSE, the ramp continues from the last stored value

Important:
The block does not automatically return to zero — it continues from the point where it stopped.

Note about TIMEBASE

• If TIMEBASE is less than the PLC cycle time, unexpected behaviors may occur
• If TIMEBASE = T#0s:
  • ASCEND and DESCEND act directly (without relation to time)
  • Limitation occurs per execution cycle

Application Example

Reference_Speed :REAL; //IN

VALUE_S :REAL := 10.0; //ASCEND 

VALUE_D :REAL := 20.0; //DESCEND 

TIMEBASE :TIME := T#1s; //TIMEBASE

RESET_RAMP: BOOL; //RESET

Operation:

• The output will increase by a maximum of 10 units per second
• The output will decrease by a maximum of 20 units per second

Figure 3. Parameterization of the RAMP_REAL block

Applications in Automation

The RAMP_REAL block is used in:

• Smooth speed control
• Avoiding spikes in systems
• Soft start and soft stop
• Gradual adjustment of analog variables
• Equipment protection

Important Notes

• Works with variables of type REAL
• Requires the Util library
• The TIMEBASE value must be consistent with the PLC cycle
• RESET holds the last output value

In summary, the RAMP_REAL block allows controlling the rate of change of a signal, ensuring smooth and safe transitions, being essential in applications that require stability and equipment protection.

Figure 4. Operation of the RAMP_REAL block