کنترل PID اینورتر چیست؟ آموزش تنظیم پارامترهای PID در درایو

How PID Control in a VFD Turns Sensor Feedback into Automatic Speed Adjustment

PID control in a variable frequency drive (VFD) automatically adjusts motor speed in response to the difference between a desired process value and the value measured by a sensor. In a pressure-controlled pumping system, for example, increased water demand may cause the measured pressure to fall. If the control loop is configured correctly, the VFD can increase pump speed to bring pressure back toward the setpoint.

This means an operator does not have to change the output frequency every time demand changes. But enabling the PID function alone is not enough. The setpoint source, feedback input, sensor scaling, control direction, command priorities and operating limits all need to be configured consistently.

This guide first explains how PID works in a VFD. It then walks through the documented PID parameters of the XIMA Industrial G Series, two different approaches to choosing a setpoint, an example using a 4–20 mA pressure transmitter, and practical troubleshooting checks.

Scope and version: The control principles are broadly relevant to VFDs that support process PID. However, the parameter codes and model-specific examples in this article refer to the XIMA Industrial G Series Installation Manual, version V5.2, firmware H3.24. Do not assume the same parameter codes apply to other XIMA drive series, hardware revisions or firmware versions. For the G Series product family and technical documentation, see the verified Industrial G Series overview and XIMA documentation and downloads.

PID Settings in the XIMA G Series: Quick Parameter Reference

If you are familiar with PID theory and need to locate a setting, start here. These codes relate to the manual version stated above; the values shown are not a universal commissioning recipe.

Do not copy the defaults as recommended tuning values. The correct response direction, frequency limits, run/enable commands and control settings depend on the actual machine and process.

What Is PID Control in a VFD, and How Does It Work?

PID stands for Proportional, Integral and Derivative. A PID controller uses the difference between a desired process value and a measured value to calculate a corrective output. In a VFD, that output can be used to adjust the frequency supplied to the motor, and therefore its speed.

A basic closed-loop system has five elements:

• Setpoint (SP): the required process value, such as 6 bar.
• Process variable (PV) or feedback: the value reported by a sensor or another supported feedback source.
• Control error: the difference between SP and PV.
• PID controller: the algorithm that calculates the corrective command.
• Motor and process: the drive, motor, pump, fan or other equipment that responds to the command.

Control loop: Setpoint → comparison with feedback → PID controller → VFD output-frequency command → motor and process → sensor → feedback to the controller.

With open-loop control, a drive might be instructed to run at 35 Hz regardless of whether process pressure changes. With closed-loop PID control, the frequency command can change as the measured process variable moves away from the target. The controller is still subject to the motor, drive and process limits: no amount of tuning can make an undersized pump produce pressure or flow beyond its capability.

Process PID is not the same as closed-loop vector motor control. Vector control is primarily concerned with motor speed and torque performance. Process PID is used to regulate a process variable such as pressure, flow or temperature using suitable feedback.

What Do the P, I and D Terms Actually Do?

A commonly used continuous-time representation is:

e(t) = SP(t) − PV(t)

u(t) = Kp × e(t) + Ki × ∫e(t)dt + Kd × de(t)/dt

This equation explains the principle; it does not establish that XIMA settings SE16, SE17 and SE18 map directly to these mathematical coefficients with identical units or scaling. Actual controller implementations vary. The process direction may also require a different treatment of control error.

Many industrial processes operate satisfactorily with PI control alone. However, the documented valid range for SE18 begins at 0.01 in the manual version used here. Therefore, do not assume that entering SE18 = 0 is an acceptable way to disable derivative action. Confirm the supported method for the installed drive and firmware.

Before You Configure PID: Five Essential Checks

1. Motor and drive: Confirm the motor nameplate data, drive rating, operating mode, acceleration/deceleration settings, permitted frequency range and motor protection. Make sure the motor operates correctly in an appropriate non-PID test before attempting closed-loop operation.

2. Process variable: Decide exactly what you need to regulate: pump discharge pressure, pressure at a remote point of use, flow rate, tank level or another measurable quantity. Sensor placement can change how the control loop behaves.

3. Sensor specifications: Check whether the transmitter provides 4–20 mA, 0–20 mA or a voltage output. Confirm its measurement span, supply requirements, wiring arrangement, accuracy and calibration from its own datasheet.

4. Commands and limits: Review Run and Enable conditions, preset-frequency inputs, minimum and maximum frequency, and independent process protection such as dry-run and overpressure safeguards.

5. Hardware and firmware version: Match the drive model and software version to the correct manual. Parameter codes should not be transferred blindly between product series.

How to Configure PID Parameters on a XIMA Industrial G Series Drive

Step 1: Select the Controller with SE15

In the referenced G Series manual, SE15 = 1 selects PID control. SE15 = 0 disables the controller, while SE15 = 2 selects On/Off control.

The manual also describes a configuration in which digital input D5 can be used to enable PID operation. In that arrangement, IO03 = 4 assigns the corresponding function to D5. Whether this approach is appropriate depends on the input wiring and the installation’s command logic; it should not be mixed with another control arrangement without verifying how priority and enable conditions work.

Check preset-frequency inputs. An active preset command can temporarily override PID operation. If the drive is running but its output does not respond to the process variable, inspect digital-input states before changing the P, I or D values.

Step 2: Choose the Feedback Source with IO15

For a compatible 4–20 mA pressure transmitter connected to I1, the corresponding choice is IO15 = 1. Selecting the input in software does not verify the physical wiring. Check transmitter supply voltage, signal return, terminal allocation and the drive’s wiring diagram separately.

Step 3: Scale the I1 Feedback Signal with IO06, IO07 and IO33

Even a correctly selected input will give misleading feedback if the current range is scaled incorrectly. In the documented G Series version:

• IO06 = 0 selects a 0–20 mA current range.
• IO06 = 1 selects a 4–20 mA current range.
• IO07 defines the upper end of the I1 current range; 20.00 mA is used in the example.
• IO33 defines the I1 current-range minimum; 4.00 mA is used here, and the manual specifies its relevance when IO06 = 1.

For a linear 0–10 bar transmitter with a 4–20 mA output, 4 mA should represent 0% of the measurement span and 20 mA should represent 100%, provided the sensor and input are scaled as intended. Do not reuse these settings for a sensor with a different range without checking calibration and the drive’s response to a lost signal.

Step 4: Set the Reference Source with IO05 — and Understand SE22 and SE23

The reference source is not the same thing as the initial reference value. On the XIMA G Series, IO05 determines where the reference command comes from. SE22 and SE23 determine the initial PID setpoint behavior.

Documented IO05 options include 0 = V1 voltage input, 2 = I1 current input, 4 = keypad +/- keys, 6 = Modbus and 7 = stepped keypad mode. Consult the full parameter table for the complete set.

SE22 defines the initial-setpoint mode:

• SE22 = 0: begin with a zero reference.
• SE22 = 1: begin with the last stored reference before shutdown.
• SE22 = 2: begin with the value specified by SE23.

SE23 defines the initial reference as a percentage. For example, with keypad-based reference selection (IO05 = 4), SE22 = 2 can establish the initial reference from SE23, subject to the keypad control logic. If the reference instead comes from V1, do not assume that entering a value in SE23 replaces the actual analog voltage at V1.

Documentation discrepancy: The referenced manual does not present the same SE23 numeric range in its main parameter table and PID summary table. The 60% example below falls within both stated ranges. For values near the documented limits, check the installed firmware and its actual parameter range. Some IO05 details also differ between the complete table and the abbreviated PID section, so do not infer factory defaults from the short summary alone.

Step 5: Verify the Control Direction and SE19

In a typical pressure-boosting system, falling pressure calls for increased pump speed. Other processes can behave in the opposite direction. The G Series manual identifies SE19 as PID Process Reverse, with normal and reverse modes.

If pressure falls but motor speed also falls when it should rise, do not immediately toggle SE19. First verify the sensor reading, the signal scaling, the selected reference source, the absence of overriding preset commands, and agreement with an independent pressure gauge. Only then assess the required control direction under safe, supervised test conditions.

Worked Example: Holding 6 bar with a 4–20 mA Pressure Transmitter

Consider a hypothetical pumping system using a XIMA Industrial G Series drive and a linear pressure transmitter. This example demonstrates signal scaling and reference selection; it is not a tested configuration for a specific installation.

Calculate the Percentage Setpoint and Feedback Current

For a 0–10 bar transmitter, a 6 bar target represents:

Setpoint (%) = (6 ÷ 10) × 100 = 60%

For a linear 4–20 mA transmitter, the output current can be estimated from:

I (mA) = 4 + [(Pressure − Pmin) ÷ (Pmax − Pmin)] × 16

At 6 bar:

I = 4 + (6 ÷ 10) × 16 = 13.6 mA

When the actual process pressure is 6 bar, a healthy and correctly calibrated transmitter should therefore output approximately 13.6 mA. This is an expected scaling check, not a guarantee of instrument accuracy.

If the sensor range changes to 0–16 bar, the same 6 bar target becomes 37.5% of span, and the expected current becomes 10 mA. A percentage setpoint is meaningless unless the associated measurement range is known.

Method A: Analog Setpoint from V1, with Pressure Feedback on I1

The manufacturer’s pressure-control example in Figure 74, printed page 153 of the G Series V5.2 manual, illustrates an analog voltage reference through V1 and a current-based pressure feedback signal through I1. The relevant settings to review are:

If V1 has been configured as a 0–10 V reference and the mapping is linear, 60% corresponds mathematically to 6 V at V1. Confirm the installed drive’s V1 scaling (including relevant voltage-range settings such as IO08), the reference signal source, and the commissioning documentation before making that assumption on real equipment.

For the manufacturer’s drawing and terminal details, open the XIMA G Series V5.2 manual from the verified downloads page and locate Figure 74 on printed page 153. The example diagram is not a substitute for the wiring diagram and transmitter datasheet for your actual equipment. In particular, the transmitter power supply must not be assumed from another device’s installation.

Method B: An Initial 60% Setpoint via the Keypad

In a separate scenario, the setpoint source can be the drive keypad. With the same 0–10 bar transmitter and 6 bar target, the following settings illustrate the relationship between the selected source and the stored initial reference:

Do not confuse Methods A and B. Method A uses an externally applied V1 reference; Method B uses the keypad and an initial value stored in SE23. In Method B, SE23 does not override the need to choose the appropriate reference source with IO05, and the keypad’s operating behavior still matters.

How to Check the Example During Commissioning

Under a properly planned and safe test, the responsible technician should compare and record:

1. Actual pressure from an independent gauge against the transmitter reading.
2. Transmitter current and the feedback percentage indicated by the drive.
3. The active setpoint, rather than merely a number entered into one parameter.
4. Run/Enable status and any active preset-frequency inputs.
5. Output frequency and its permissible minimum and maximum.
6. Steady-state performance, overshoot and pressure changes following a small, controlled change in demand.

The G Series also offers monitoring/display options. For example, the documented use of IO10 may help display a control-variable or feedback percentage depending on the selected display configuration. Panel monitoring does not replace an independent calibrated pressure gauge.

How to Tune VFD PID Settings and Reduce Pressure Oscillation

There is no single set of P, I and D settings that works for every pump, fan or industrial process. If the sensor is scaled incorrectly or the pump cannot reach its target at the permitted speed, repeatedly changing controller gains is unlikely to solve the underlying problem.

1. Validate the feedback. With pressure physically steady, check whether the sensor signal also remains reasonably steady. Separate electrical noise, poor wiring, incorrect signal common, sensor position and real pressure fluctuations.

2. Check the response direction. Observe whether a small, controlled change in drive output moves the process variable in the expected direction. Do not change SE19 on a hunch.

3. Check process capacity and output limits. Ensure the drive is not already pinned to its minimum or maximum frequency and that the driven equipment is capable of meeting the setpoint.

4. Assess proportional action. Under documented test conditions, small changes to SE16 can be assessed for their effect on response speed and oscillation. Excessive proportional action can cause repeated overcorrection.

5. Assess integral action. SE17 helps address steady-state error, but too much integral action can aggravate overshoot and hunting, particularly when the output has been saturated at a limit.

6. Consider derivative action only when justified. SE18 can influence transient response but may be sensitive to noisy measurements. Do not assume that zero is a supported value in the referenced firmware.

7. Make tests repeatable. Record the target, measured value, output frequency, parameters changed and observed response. Reaching the setpoint once is not proof of a stable control loop.

Troubleshooting XIMA VFD PID Control: Symptoms, Checks and Likely Causes

Why Does Using the Same Source for Setpoint and Feedback Matter?

The manufacturer’s manual notes that choosing the same input source for the reference and feedback may cause the motor to remain at a constant frequency. That makes IO05 and IO15 an essential first check. In Method A above, V1 supplies the reference and I1 supplies feedback, so the two signals serve distinct purposes.

Why Can a Preset-Frequency Input Override PID?

According to the G Series manual, preset-frequency commands can take priority over PID operation while the corresponding input is active. Consequently, a lack of response to P or I adjustments does not automatically mean the drive or PID algorithm is faulty.

Is Pressure Hunting Always a PID Tuning Problem?

No. A noisy sensor, poor transmitter location, pressure-vessel issues, check valves, changing demand, pump limitations and ramp times can all contribute. Separate measurement and process problems from controller behavior before attempting to retune PID.

Where Is PID Used in VFDs, and What Are Its Limits?

Pump pressure control: By varying motor speed, a drive can help maintain pressure as consumption changes, provided the pump, sensor and safeguards are correctly selected. For related equipment guidance, see XIMA’s verified pump VFD selection guide and booster-pump control and wiring guide.

Flow and tank level: Where a suitable sensor is available and pump speed meaningfully influences the measured variable, PID may be one part of the solution. Overflow prevention and dry-run protection require independent attention.

Temperature: When changing fan or circulation-pump speed genuinely influences process temperature, a PID loop may help regulate it. Thermal delays and correct action direction need special consideration.

Web or material tension: In winding and unwinding equipment, tension may be influenced by speed or torque. These installations need dedicated mechanical and control design, not a generic PID recipe.

PID vs On/Off Control in a Drive

PID continuously adjusts its control output in response to error. On/Off control makes discrete decisions based on thresholds and, where appropriate, hysteresis. In the referenced G Series, SE15 distinguishes the two modes: 1 for PID and 2 for On/Off. PID is not automatically the best choice for every application.

Should PID Run Inside the VFD or in a PLC?

For a simple process with a single feedback loop, the VFD’s internal PID may be sufficient. For multiple coordinated variables, complex sequences or multi-pump systems, a PLC or central process controller may be more appropriate. Avoid designing two independent controllers that issue conflicting commands for the same frequency reference. For communications context, see XIMA’s verified VFD-to-PLC communication guide using Modbus RTU.

Safety Measures That PID Control Must Never Replace

1. Electrical installation, motor-power wiring and control-circuit changes must be carried out by qualified personnel following the drive manufacturer’s instructions. Isolate the equipment, observe the specified discharge interval and verify the absence of hazardous voltage before accessing electrical parts.
2. Never guess a pressure transmitter’s supply-voltage requirements. Match the actual device datasheet to the correct wiring diagram and terminal ratings.
3. Set permitted pressure, speed, flow and motor-current limits according to the equipment and the process design.
4. Include feedback loss, sensor wiring faults, out-of-range measurements and output saturation in the installation’s risk assessment.
5. PID software is not a substitute for pressure-relief devices, independent overpressure protection, dry-run protection, emergency-stop systems or other necessary safety functions.
6. Keep a record of the drive model, firmware, changed parameters, test conditions, results and date of commissioning.

Frequently Asked Questions About VFD PID Control

What parameter enables PID on the XIMA G Series?

In manual V5.2, SE15 = 1 selects PID control. The manual also describes PID activation through an appropriately assigned D5 digital input in the relevant configuration.

Which parameters matter for a 4–20 mA pressure transmitter?

When I1 is used for feedback, check IO15 = 1, IO06 = 1, the upper current limit IO07, and the lower current limit IO33. The sensor’s actual wiring, power requirements and calibration must also be verified.

What is the difference between IO05 and IO15?

IO05 chooses the reference source, while IO15 chooses the feedback source. Confusing the two can produce a control loop that does not respond as intended.

How do SE22 and SE23 differ from IO05?

IO05 selects where the reference comes from. SE22 defines the initial PID setpoint mode, and SE23 stores the initial percentage value used by the relevant mode. These settings need to be considered together.

What percentage and current correspond to 6 bar on a 0–10 bar transmitter?

Six bar is 60% of a 0–10 bar span. For a linear 4–20 mA sensor, the expected output is 13.6 mA, assuming correct calibration and scaling.

Can I set SE18 to zero to remove derivative action?

Do not assume so. In the referenced firmware manual, the listed SE18 range begins at 0.01. Verify any supported PI-only arrangement for the installed drive before entering an undocumented value.

Why does the frequency remain unchanged even though PID is enabled?

Possible explanations include incorrect or identical reference and feedback sources, an active preset input, missing Run/Enable conditions, output-frequency limits, or insufficient process capacity.

Does PID control always save energy?

No. Energy savings may occur in applications such as variable-demand pumps and fans when motor speed can be reduced appropriately. The result depends on the duty cycle, pump or fan operating point, system losses and equipment efficiency, and should be measured rather than assumed.

Can I use these parameter codes on every XIMA drive?

No. The codes and examples here are specific to the documented Industrial G Series version. Always consult the manual and firmware information for the actual drive model.

Final Checklist: Setting Up PID Correctly on a XIMA G Series VFD

Start by identifying the process variable and sensor. Then select the reference source (IO05) and feedback source (IO15) independently, and verify the signal scaling with IO06, IO07 and IO33 as applicable. Confirm the selected controller mode (SE15), Run/Enable conditions, preset priorities, control direction and permissible frequency range before tuning SE16–SE18 based on observed process response.

For the pressure-control example in this article, remember that an analog V1 reference and an initial keypad setpoint through SE22/SE23 are separate approaches. Both require independent measurement, safe commissioning and validation on the actual equipment.

For model selection, reference documents or application support, visit XIMA’s verified product listing, documentation library or contact page.

Technical source: XIMA Industrial G Series Installation Manual, V5.2 (firmware H3.24), including the system and I/O parameter tables, the PID control chapter and the pressure-control example in Figure 74 (printed page 153). The manual is available through the verified download page. This article is an educational interpretation of the documented settings, not a record of a real-world commissioning test.