Application of Pid AI-808 Controller

Abstract: This paper introduces the performance, parameter setting and application of the Yudian pid controller AI-808 in the liquid level detection automatic control system.

Key words: Automatic control, Controller, Ultrasonic

Foreword: In the Yongping Copper Mine Concentrator of Jiangxi Copper Company, the original 4 seats of sand pump pools which are controlled by automatic liquid level. Because the imported E27 series controllers used in the control system are expensive, with the gradual aging of the internal components of the controller, The failure rate had increased significantly. The use of domestic instruments to replace imported controllers has become prior choices. In January, 2001, after the analysis and comparison, Yudian AI-808 artificial intelligence controller are used to control concentrator on the tailing pumpliquid level control, with VEGASON52K liquid level gauge, DFD-1000 handheld actuator and ZKJ-210 actuator. Together, the 3# pump pool liquid level automatic control system of 2# pumping station was formed. After the on-site and system parameter setting, the automatic control of the pumping tank liquid level was successfully achieved and good results were obtained.

Introduction of AI-808 controller

The AI-808 controller is an advanced instrument in China. It uses a high-performance ASIC chip and modular hardware design with digital correction technology on both input and output signals to eliminate unstable resistors. The error caused by the automatic zero adjustment technology can be used for a long time without zero drift, and the measurement is accurate and stable; it has various specifications for input and output and alarm mode settings. It not only has manual/automatic bumpless switching function, but also has manual auto-tuning and valve output, and is used as a proportional output of the servo amplifier to directly control the valve. The power supply can fluctuate within a wide range of 85-264VAC (50-60HZ). In the strong interference environment, the measurement accuracy and the stability of the work can be guaranteed.

Pump tank liquid level automatic control and wiring principle are shown in Figure 1, Figure 2

Figure 2

The realization of the automatic control function of the pump pool liquid level is converted into a 4-20mA current output signal by the liquid level gauge VEGASON 52K, which is sent to the controller AI-808 through the resistor, and it performs data analysis and processing, according to control function requirements, drive the intermediate relay 1ZJ or 2ZJ, control the positive and backward rotation of the ZKJ-210 actuator, adjust the oil quantity of the sand pump hydraulic coupler, so as to increase or decrease the sand pump output power, stabilize the pump The purpose of the pool level.

Functions and parameter setting of controller AI-808  

Functions of AI-808

The correct parameter settings of the AI-808 controller is the key to control the liquid level automatically. There are 23 parameters to be set, and 8 field parameters need to be defined. The parameter codes and values for setting are shown as below

Parameter code/value

HIAL upper limit alarm 85 (see Note 1)

LOAL lower limit alarm 50 (see Note 2)

DF backlash 0.3

CTRL control mode 5 (see note 3)

M5 keeps parameters 2.0

P rate parameter 2

T lag time 3 seconds

CTL output cycle 4 seconds

SN output specification 33 (see Note 4)

DIP decimal point position 1

DIL input lower limit display value 0

DIH input upper limit display value 100

SC main input translation correction 0

OPI output mode 5 (see Note 5)

OPL output lower limit 0

OPH output limit 100

ALP alarm output setting 15 (see Note 6)

CF system function selection 15

ADDR communication address 0

BAUD communication baud rate 9600

DL input digital filtering 1

RUN running status and power-on display processing 1 (see Note 7)

LOC parameter modification level 1 (see note 8)

EP1—EP8 Field Parameter Definition (See Note 9)

Setting instructions

1. The upper limit alarm value is set according to the control requirements of the pump pool level, and it is necessary to consider the operator's processing time.

2. The lower limit alarm value is set to prevent the pump or air from entering the pump and to signal the alarm in advance.

3. CTRL=5, indicating that the AI-808 regulator acts as a servo amplifier, and the meter outputs the measured value directly as an output value.

4. Input specification Sn=33, indicating that the input is a 1-5VDC signal.

5. OPI=5, indicating the position proportional output without valve feedback signal. The main output and alarm 1 control relay directly drive the ZKJ-210 actuator forward and reverse.

6. ALP=15, indicating that the upper and lower limit alarms are all output by AL2, and the alarm symbol (high HIAL, low LOAL) is displayed alternately on the lower display, so that the operator can quickly understand the cause of the instrument alarm.

7. RUN=1, indicating that the instrument is working in automatic state.

8. Parameter modification level, LOC=1, indicating that the field parameters can be displayed and not allowed to be modified, but the set value is allowed to be set. Through the setting of the parameter lock function, the unrelated personnel are prevented from moving and affecting the normal operation of the instrument.

9. When the parameters of the controller are set, most parameters no longer need to be set by the field workers. And if the field operator does not understand many parameters, it may cause misoperation and change the parameters to the wrong value, which affects the normal operation of the instrument. Therefore, the operator should understand parameters that are showed above.

Instrument installation and commissioning

VEGASON52K ultrasonic level gauge

Firstly, make sure the controller is power-on, and the parameters are set according to the actual liquid level change at the pump pool site, such as the type, range, and output signal and the simulation is performed before installation according to the technical requirements. The level of the bit changes linearly with the output signal. Since the tailings pump pool is an open container, it is necessary to maintain a certain distance between the meter and the container wall when manufacturing the probe position frame, that is, to avoid the blind pressure of the detection; and to keep the central axis of the sensor perpendicular to the surface of the medium. At the same time, there should be no other debris in the cone-shaped emission angle of the ultrasonic sensor to avoid false echoes and affect the accuracy of the measurement.

Commissioning of DFD Communicator and ZKJ-210 Actuator

DFD-1000 electric operator adopts the principle of “switch operation system” to switch/operate manually/automatically. When the switch is in the manual position, the input ports of 1 and 2 are open to the output ports of (11) and (12) respectively. The switch controls both the port (11) and (12) which are energized, and controls the length of the energization time according to the magnitude of the position feedback signal; when the switch is in the automatic position, 1 is connected to (11), and 2 is connected to (12). The AI-808 controls the ZKJ-210 angular stroke according to the liquid level change, adjusts the sand pump output power, and stabilizes the pump pool level.

After the instrument is connected to the control line as required, the consistency of the change of the angular stroke and position feedback signal of the ZKJ-210 actuator is adjusted, and the full scale of the actuator angular stroke zero is adjusted by the coarse adjustment. Corresponding to the output signal 4-20mA (indicated on the DFD meter head), and manual operation with the operator to test, and check whether the 1XC and 2XC travel limit switches meet the specified technical limit requirements.

System debugging

Dynamic system debugging is the most important step to achieve automatic liquid level control. Firstly check whether the AI-808 controller can realize manual control adjustment through the intermediate relay, and the consistency of the positive and negative control directions of the actuator, and then check the liquid level high and low alarm function, the stroke control switch limit and the protectional function are normal. After the manual test is completed, the pump pool level is stabilized by manual control within the range required by the process. The DFD-1000 hand-operator is the first directed to the automatic control, and then the AI-808 is put into the automatic viewing. The automatic control system can be dynamic change of the liquid level is adjusted accordingly, and then the self-tuning function is started to obtain the optimal system control parameters. After the self-tuning is finished, record the system control parameters.

Effect

After more than 2 months of actual operation and assessment, the liquid level automatic control fully meets the specified technical requirements, and because of the additional low alarm function, it can also play a role in preventing the sand pump.

Conclusion

The E27 series controller is the main original control system for pump tank liquid level and the actuator has a high failure rate. The cost of Yudian controller AI-808 is relatively lower. The digital display is intuitive and easy to operate. High and low alarm outputs improves the function and stability of automatic control.