Control of ammonia compressor in wax making unit o

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The control system (III) of ammonia compressor of wax making device in refinery of Daqing Oilfield Chemical Complex

l disconnection alarm screen

this system has automatic disconnection diagnosis function. If the analog signal line connected to the programmable controller is open circuit, the measured value will become a black box (Figure 8), for example, the inlet pressure signal line is open circuit

· alarm screen

when a fault occurs in the operation process, the system will automatically record the fault. We found that DSM is a very professional parameter, time, type, alarm level, etc. As shown in Figure 9

v. configuration process

the process of configuration is essentially the process of connecting the buttons, alarms, trends and other graphic objects on the configuration screen with the on-site execution equipment or instruments, so that the operator can operate and monitor the on-site execution equipment and instruments on the operation station screen. The following takes the control process of adding slope as an example to illustrate the process of force control software configuration

1 establish a real-time database

click "real-time database configuration" in the navigator of draw, start the real-time database configuration program, create new data points, and set necessary alarm parameters

2 create button

first draw the button in the draw of the force control software, then right-click and select the attribute. We are just rebuilding the existing material property from "text" to "slope addition", select a suitable color, and finally click the "OK" key

3 add script

in the configuration state, open the slide valve operation screen, double-click the "slope add" button, and then the animation connection main dialog box appears. Select the "general action" under the "touch sensitive action" option, click the general action button, and a script appears. Write the following script in the script. “ysjk1=1”。 Ysjk1 is a pre-defined DB variable

4 establish i/o data connection

that is, the connection with PLC address and data bit is realized in dbman of force control software. In dbman, you must first create a new point plus ysjk1, and connect the data of the created points. (before data connection, first add the specific PLC to be connected to the i/o drive equipment)

as shown in Figure 11, after connecting the data, the variable ysjk establishes a connection with the 11th bit of channel 90 in the IR area (internal relay area) of OMRON PLC, thus realizing the purpose of controlling the field compressor through PLC in the operation station

5 PLC programming and debugging

when the PLC program debugging is correct, carry out system joint debugging. The figure is part of the program

VI. the prospect of force control software in the field of compressor control

at present, in most of China's industrial enterprises, the control of imported compressors is mostly supported by manufacturers, and generally needs to be transformed after several years of operation; Some domestic compressors are equipped with imported automatic control equipment and software before leaving the factory, which makes the price comparison between the automatic control system and the unit unbalanced, which is difficult for users to accept. In addition, some domestic compressors are equipped with incomplete automatic control systems for manual lowering of the workbench, which affects the overall sales and market of the unit. Therefore, configuration software is promising in the monitoring of large units

it is difficult to clean the wax making workshop of Daqing oilfield chemical plant. Since the ammonia compressor control system was put into use, not only the labor efficiency and product qualification rate have been greatly improved, but also the work intensity has been reduced, the operation and maintenance have been simplified, and the economic benefits of the workshop have been significantly improved

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