DVP-PLC Application Manual Programming

1 DVP-PLC Application Manual Programming . Table of Contents Chapter 1 Working Principles of PLC Ladder Diagram Preface-The Background and Functions of PLC .. 1-1. The Working Principles of Ladder 1-1. The Difference between Traditional Ladder Diagram and PLC Ladder Diagram .. 1-2. Edition Explanation of Ladder Diagram .. 1-4. The Edition of PLC Ladder Diagram .. 1-8. The Conversion of PLC Command and Each Diagram Structure .. 1-11. The Simplification of Ladder Diagram .. 1-14. The Example for Designing Basic 1-16. Chapter 2 DVP-PLC Function Summary of DVP-PLC Device Number .. 2-1. Value, constant [K] / [H] .. 2-7. The Numbering and Function of External Input/Output Contact [X] / [Y] .. 2-9. The Numbering and Function of Auxiliary Relay [M] .. 2-11. The Numbering and Function of Step Relay [S] .. 2-12. The Numbering and Function of Timer [T] .. 2-13. The Numbering and Function of Counter [C].. 2-16. Register Number and Function [D], [E], [F].

2 2-28. Data register [D] .. 2-28. Index Register [E], [F] .. 2-29. File Register Function and Characteristics .. 2-30. Nest Level Pointer[N], Pointer[P], Interrupt Pointer [I] .. 2-30. Special Auxiliary Relay and Special Register .. 2-33. Special Auxiliary Relay and Special Register 2-53. Fault Code Information .. 2-84. Chapter 3 Basic Commands Summary of Basic Command and Step Ladder Command .. 3-1. Basic Commands Explanations .. 3-3. Chapter 4 Step Ladder Commands Step Ladder Command [STL], [RET] .. 4-1. Sequential Function Chart (SFC) .. 4-1. Step Ladder Command Explanation .. 4-2. Reminder of Design on the Step Ladder Program .. 4-7. Categories of Procedures .. 4-8. IST command .. 4-18. Chapter 5 Application Commands Summary of Parameters .. 5-1. Application Command Structure .. 5-7. Handling of Numeric Values .. 5-12. Index register E, F .. 5-15. Index for Commands .. 5-17. Chapter 6 Application Commands API 6-1.

3 Chapter 7 Application Commands API 7-1. Chapter 8 Application Commands API 100-149 .. 8-1. Chapter 9 Application Commands API 150-199 .. 9-1. Chapter 10 Application Commands API 215-246 .. 10-1. 1 Working Principles of PLC Ladder Diagram Preface----The Background and Functions of PLC. PLC (Programmable logic Controller) is one of electronic equipments. It was called Sequence Controller . before. It was named Programmable logic Controller (PLC) by NEMA (National Electrical Manufacture Association). in 1978 and defined as electronic equipment. The operation of PLC is in the following: Step 1. Read the external input signal, such as the status of keypad, sensor, switch and pulse. Step 2. Using microprocessor to execute the calculations of logic , sequence, timer, counter and formula according to the status and the value of the input signal read in the step 1 and pre-write programs saved inner to get the corresponding output signal, such as open or close of relay, operation of controlled machine or procedure to control automatic machine or procedure of manufacture.

4 PLC also can be used to maintain and adjust of production program by editing or modifying the peripheral equipments (personal computer/handheld Programming panel). The common program language of PLC is ladder diagram. There are stronger functions in PLC with the development and Application requirements of electronic technology, such as position control, network and etc. Output/Input signals are DI (Digital Input), AI (Analog Input), PI (Pulse Input), DO (Digital Output), AO (Analog Output) and PO (Pulse Output). Thus PLC plays an important role in the feature industry. The Working Principles of Ladder Diagram Ladder diagram is an automatic control diagram language that developed during World War II. At first, it just has basic components, such as A contact (normally open), B contact (normally close), output coil, timer counter and etc. (The power panel is made up of these basic components) It has more functions, differential contact, latched coil and the Application commands, add, minus, multiply and divide calculation, that traditional power panel can't make since PLC is developed.

5 The working principles of the traditional Ladder Diagram and the PLC Ladder Diagram are similar to each other;. the only difference is that the symbols for the traditional ladder diagram are expressed in the format that are close to its original substance, while those for the PLC ladder diagram employ the symbols that are more explicit when being used in computers or data sheets. In the Ladder Diagram Logics, it could be divided into the Combination Logics and the Sequential Logics, and is described as follows: 1. Combination Logics: The following example is the combination logics that show in traditional diagram and PLC ladder diagram separately. Traditional Ladder Diagram PLC Ladder Diagram X0 Y0 X0. Y0. X1 Y1 X1. Y1. X2 X4 Y2 X2 X4. Y2. X3 X3. DVP-PLC Application Manual 1-1. 1 Working Principles of PLC Ladder Diagram Example 1: Circuit 1 utilizes one X0 (NO: Normally Open) switch, which is normally known as the A switch or contact, and its characteristic is that the contact is in the OFF condition at regular time (not pressed); the output point Y0 is thus in OFF condition.

6 However, once the switch motion (the button is pressed) is conducted, the contact will be ON, and the output point Y0 will be in ON condition. Example 2: Similarly, Circuit 2 utilizes the X1 (NC: Normally Close) switch, which is normally known as the B switch or contact, and its characteristic is that the contact is in the ON condition at regular time; the output point Y0 is thus in ON condition. While the switch motion is conducted (which is in the OFF condition), the output point Y0 is in OFF condition. Example 3: This is an example of combination logics output, which has more than one input equipment. The output point Y2 will be in ON condition when X2 is in OFF condition or X3 and X4 are in ON condition. 2. Sequential logics: The sequential logics are a type of circuit that possesses the Draw-Back structure, which is to draw back the circuit's output result and has it serve as the input condition.

7 Thus, under the same input condition, different output results will be generated in accordance with previous conditions and motions with different orders. The following example is the sequential logics that show in traditional diagram and PLC ladder diagram separately. Traditional Ladder Diagram PLC Ladder Diagram X5 X6 Y3. X5 X6. Y3. Y3 Y3. When the above circuit is just supplied with power, although the X6 switch is ON, the X5 switch is still OFF, thus, the output relay Y3 will be in OFF condition; output of the relay will only be ON after X5 is ON. Once the output relay Y3 is in ON condition, there will be a feedback signal containing the ON condition from Y3 to connect in parallel with the A contact of X5; this circuit is thus also known as the self-latched circuit. The circuit motion is showed in the following chart: Device status X5 X6 Y3. Step 1 N N OFF. 2 Y N ON. 3 N N ON. 4 N Y OFF. 5 N N OFF.

8 N: is in OFF condition Y: is in ON condition From above chart, you can find that the same input may get different result. For example, in the step 1 and 3, the status of X5 and X6 are in OFF condition but Y3 is in OFF condition in step 1 and in ON condition in step3. That is due to the self-latched circuit feedback input. In this example, it explains with contact A, contact B and output coil. The usage of other equipments is the same with this. Please refer to the chapter 3 for the detail. The Difference between Traditional Ladder Diagram and PLC Ladder Diagram 1-2 DVP-PLC Application Manual 1 Working Principles of PLC Ladder Diagram Although the working principles are in accordance with each other for the traditional ladder diagram and the PLC. ladder diagram, PLC is indeed utilizing the microcomputer chip (MCU) to simulate the motion of the traditional ladder diagram, which is to use the scan method to look over one by one the conditions of all input devices and output coils, and afterwards, with the conditions in consideration, to calculate and generate the same output result as that of the traditional ladder diagram based on the logics of the combination status of the ladder diagram.

9 However, since that there is only one MCU, the only way to examine the circuits is to look it over one after another within the ladder diagram program, then calculate the output result in compliance with the program and the input/output status, and finally, output the results to the external interface; thereafter, start over with the readout of the input status, the calculation, output, and repeatedly go over the above-mentioned motions again; the time needed to complete the whole set of cyclic motion is called one Scan Time. The scan time will become longer in accordance with the increment of the program. With this scan time, it will incur repeated input detections, and thus, result in delay in the output responses; and the longer the delay time, the greater the error towards the control, and what's worse, is that the condition might be unqualified for the control requests. By then, PLC (with faster Scan Time) would be chosen to do the job; the scan speed is thus an essential specification to PLC.

10 Thanks to the advanced technique of ASIC (IC. with specific functions) within the microcomputer, PLC of the present has made greater progress in the scan speed, and what follows is the scanning chart of the PLC Ladder Diagram Program. Read input state from outside X0 X1. Start Y0. Y0. Calculate the result by ladder diagram algorithm (it doesn't sent X10. M100 X3. to the outer output point but the Execute in cycles Y1. inner equipment will output : immediately.) : X100 M505. Y126. End Send the result to the output point In addition to the difference of scan time, PLC ladder diagram and traditional ladder diagram also has difference in reverse current . In the following chart of traditional ladder diagram, if X0, X1, X4 and X6 are in ON condition and the others are in OFF condition, output point Y0 will be in ON condition as shown as dotted line in the following diagram. But in the PLC ladder diagram will have error in the peripheral equipment WPLSoft due to scan method of MCU is from up to down and from left to right.