Application of the hottest wireless communication

2022-08-13
  • Detail

The application of wireless communication technology in self-propelled trolley

the original four self-propelled trolley lines in the assembly workshop of Dongfeng Erqi heavy duty truck factory are synchronized with the plate chain due to the process needs, and the infinite speed regulation of the plate chain is realized on the self-propelled trolley. It is necessary to transmit the analog quantity of the speed of the plate chain to the trolley in real time, and the equipment is transformed on the basis of retaining the original PLC. The reconstruction period is very short, with only about 10 days of high temperature leave. It is required that all four self-propelled car lines be reconstructed in place and meet the production needs of the first day of work, without any omissions

at present, the traditional sliding contact line control mode is relatively complex, and the construction time is long. The assembly workshop has considered other sliding contact line data communication modes, such as Siemens rail amplifier PROFIBUS communication mode. However, due to the short transformation time, many transformation lines and matching with the original OMRON PLC, the above methods are difficult to achieve under this requirement. Finally, we consider using advanced wireless communication technology. After deciding to adopt the wireless solution, we finally selected the Phoenix Contact wireless communication product solution based on the stable and mature application and cost performance

system functions

1 Design advantages

(1) all control signals are transmitted wirelessly, which only needs to provide power for the car, without complex wiring, reducing the number of sliding contact wires and carbon brushes, reducing the mechanical wear and carbon brush consumption caused by sliding, and greatly reducing the cost of spare parts and personnel maintenance

(2) the traditional sliding contact line control method is limited by the number of sliding contact lines. The control signal of the trolley adopts the coding method. Once the contact is poor, it is easy to have error codes and code drops, and the trolley failure rate is high. The wireless communication mode is adopted, and the 2.4G Band Bluetooth communication protocol ensures real-time communication. Through the frequency hopping spread spectrum technology, the system is anti-interference, stable and reliable, and the failure rate is greatly reduced

(3) to ensure the basic control and protection functions, the control mode of the sliding contact line needs to adopt the way of line segmentation and on-off to transmit the signal. The signal is limited by the number of sliding contact lines, which can only ensure the basic control and protection functions. The adoption of wireless mode can break through the limit of sliding line, add more control and protection functions, and make the operation protection of the car more comprehensive, reasonable, safe and reliable

(4) strong operability and good expansibility. There is no complex wiring circuit on the trolley, which avoids trolley failure. All trolley diagnosis operations and parameter settings can be carried out in the ground master control, reducing climbing operations. Even if the parking position is modified, or the number of trolleys changes, process changes, etc., there is no need to make hardware changes such as sliding contact lines, but only need to do the corresponding main control commissioning

(5) the trolley can realize automatic speed adjustment according to the speed change of peripheral interlocking equipment, and the frequency change is very flexible, which greatly improves the standardization of equipment

2. Hardware configuration

Table 1 is a list of main hardware configured with one of the bicycle trolley lines. The main control unit is composed of PLC controller and wireless base station FLM BT BS 3. As the interface device between i/o and PLC controller, the wireless base station can be connected with OMRON PLC CJ1 with low porosity through DeviceNet Fieldbus

3. Working principle

the main control PLC completes all logic control. All signals such as switch status, position information, motion status and speed information on the trolley are collected and exchanged through the wireless i/o module. These information arrive at the PLC unit through the base station. The PLC completes all logic operations through program execution, and then transmits the execution results to the wireless i/metal free spraying team on the trolley through the base station. After knowing the customer's requirements, the O module outputs them, so as to complete the actions and movements required by various processes, The working principle is shown in Figure 1. The ground master station and aerial trolley are shown in Figure 2 and figure 3

installation and debugging

1 Programming id-plug

id-plug is the identity card of each i/o, and it is the premise to determine which base station this i/o communicates with. In order to communicate with the base station, a single i/o module needs to connect data, and this connection data is saved in the id-plu2 is to cultivate advantage enterprise g inserted into the module. Before starting the i/o module, write the connection data from the base station to the i/o module. The specific steps are as follows:

(1) confirm that all connections are correct; Power up the base station

(2) set the appropriate module address on the "TN" rotary coding switch

(3) insert ID plug The id-plug light turns yellow first and then green

(4) pull out the programmed id-plug

(5) insert ID plug into i/o module

setting steps:

(1) confirm that the programmed id-plug has been inserted into the i/o module

(2) confirm that the base station is configured correctly

(3) power on the base station, and the length and number of process data of all connected i/o devices can be read from the rotary coding switch

(4) configure the local bus, and then start the local bus

(5) if the base station does not establish a communication connection to the i/o module, the error bit in the status word will be set, and the BT light will display red

(6) once the wireless Bluetooth network communication is established, a logic detection is performed. If the process data length is not set correctly, the BT light will flash red, indicating that an i/o error has occurred

(7) when the logic detection is completed, the BT light will display green, indicating that the i/o module can exchange data

fail safe: when the wireless connection with the i/o module is interrupted, that is, the communication fails, the i/o module will switch to the fail safe mode, the process data transmission with the i/o module will be interrupted, and all process data will be set to zero; When the communication is interrupted and restored, the "set failsafe mode run" instruction must be used to exchange the process data of the i/o module. The status of wireless communication can be queried through the "get error code" command

the settings of the base station are shown in Table 2

2. Coupler setting

after the base station is set, the coupler can be set. The specific steps are as follows:

(1) confirm that all connections are correct

(2) power on

(3) the slave station reads the local bus of its BT network: there are two switches X1 and X10 in the coupler, turn X1 to B, then turn X10 to D, and wait for 5S; Run flashes the red light until it does not flash, then dial X10 to e and wait for 5S; When the run flashes yellow, turn X10 to f and wait for 5S; When the run light flashes green and does not flash, reading the local bus of the slave station is completed; Power on again

(4) set the baud rate of the slave station (the default is the adaptive baud rate, which is usually not needed): Dial X1 to the required baud rate (0:125k, 1:250k, 2:500k, 3: adaptive), then dial X10 to D, and wait for 5S; Run flashes the red light until it does not flash, then dial X10 to e and wait for 5S; When the run flashes yellow, turn X10 to f and wait for 5S; When the run light flashes green and does not flash, reading the local bus of the slave station is completed; Power on again

(5) set the node address: after completing the above work, finally set the node, and set X1 and X10 as the required node address; Power on again

vicenet master station setting

only when the input and output control words are correctly set, the DeviceNet master station will not report an error. Note that when there are three trolleys in the i/o address allocation, the i/o address corresponding to id-plug is reversed, that is, the address corresponding to car 3 is the first, followed by car 2 and car 1 (see Table 3). From the perspective of customers

conclusion

at present, this project has been running safely for more than a year and has achieved the expected goal. The wireless communication controlled self-propelled car has been quite stable since its installation and commissioning. Through this project, it has been proved that Phoenix Contact wireless network communication is reliable. It can give full play to its advantages in the automatic control system of circular self-propelled trolley, and has a high cost performance ratio. It is a brand-new application in the domestic wireless network used in the transportation system of self-propelled trolley for general assembly, especially in the reconstruction project of self-propelled trolley. (end)

Copyright © 2011 JIN SHI