[1] Does the PLC output not have a power supply? For example, if I want to control a 110V relay, do I need to add a power supply? How do I wire it?
A: The PLC's output port is merely a switch to drive the load; it doesn't have its own power supply. If you want to control a 110V relay, you need to add a power supply. The PLC's output is connected to the relay coil, and the relay is also connected to a 220V AC power supply. The PLC's COM terminal is also connected to a 220V AC power supply.
[2] Why are there no X8 and X9 addresses for the input port?
A: The input and output relays of Mitsubishi PLCs are addressed in octal, so they can only be X0-X7, and there are no X8, X9, and the address after X7 should be X10.
[3] Does the PLC output circuit need to be equipped with a fuse?
A: A fuse needs to be added to the PLC output circuit because if the load experiences a short circuit or fault, it can easily burn out the contacts or transistors, and also burn out the printed circuit board where the output circuit is located. Therefore, a fuse that provides short-circuit protection needs to be added to the load circuit.
[4] I want to use the programming port of the PLC to communicate with the frequency converter. Is that possible?
A: Mitsubishi FX PLCs can communicate with inverters using their built-in programming port, but you must use inverter-specific communication commands. Due to limitations of the communication protocol, inverter communication commands are not applicable to all brands of inverters. Generally, Mitsubishi PLC inverter communication commands can only communicate and control Mitsubishi inverters, and cannot communicate and control inverters from other brands.
[5] How do I connect the FX2NPLC to the touchscreen? What parameters do I need to set?
A: To connect the FX2NPLC to the touchscreen, you can use the round port of an SC-09 cable to plug into the PLC's programming port and the serial port to the touchscreen's serial port. Additionally, you need to configure the PLC type as FX2N, the interface type as RS232, and set the port, baud rate, etc., in the system parameter settings on the touchscreen. The port, baud rate, parity, data bits, and stop bits settings in the PLC programming software must match the touchscreen settings. This will allow you to connect the FX2NPLC to the touchscreen.
[6] Teacher, will the program be lost if the battery of the FX2NPLC is removed?
A: Generally speaking, because PLCs have internal charging capacitors, even if the battery is removed, the charge on the capacitors is enough to keep the data in the RAM for a period of time. Therefore, if you remove the battery and replace it with a new battery within a short time (usually 5 minutes), the program will not be lost. However, if you remove the battery and do not replace it with a new battery for a long time, the program will be lost.
[7] I would like to inquire which PLC can be directly replaced by Mitsubishi FX1N and 2N. Mitsubishi's official website has announced that 1N and 2N have been discontinued. We have some equipment that uses these two models, and we would like to find a direct replacement as soon as possible to prepare for emergency use.
A: You can choose the FX3U PLC, but before replacing it, you must check whether the instructions used in the original program are supported by the FX3UPLC, and whether the relevant system memory used in the original program is the same as that of the FX3UPLC. Only if they are the same can you replace it.
[8] Teacher, I want to connect a passive switch to the input port of the FX3UPLC. XO-X3 uses the built-in 24V power supply, while X10-X13 uses an external power supply. How should I wire it?
answer:
[9] How should a PNP type three-wire proximity switch be connected to the input port of an FX3UPLC?
A: Connect the signal output terminal of the PNP three-wire proximity switch to the PLC's input port, such as X0. Connect the 0V terminal of the PNP proximity switch to the 0V terminal on the PLC. Also, short-circuit the S/S terminal to the 0V terminal. Connect the +24V terminal of the PNP proximity switch to the 24+ terminal on the PLC. If using an external 24V power supply, connect the signal output terminal of the PNP three-wire proximity switch to the PLC's input port, such as X0. Connect the 0V terminal of the PNP proximity switch to the negative terminal of the external 24V power supply. Also, short-circuit the S/S terminal to the negative terminal of the external 24V power supply. Connect the +24V terminal of the PNP proximity switch to the positive terminal of the external 24V power supply.
[10] The scanning cycle of the PLC is fixed. How do I know if the program I wrote exceeds the inherent scanning cycle? What methods are there to find out, and how can I extend the scanning cycle?
A: To find out the current scan cycle, you can read it directly from the PLC's special register D8010. If the PLC has a special memory that can be used to set a constant scan cycle, you can change the scan cycle time by simply setting a specified value in this special memory.
[11] Does "MOVK0K2Y0" mean to reset Y0-Y7? Then why does "MOVK1K2Y0" not set Y0-Y7 but only set Y0?
A: K2Y0 in the instruction is a combination bit element, representing Y0-Y7. The MOVK0K2Y0 instruction sends 0 to K2Y0, which actually sends a binary number. The binary representation of 0 is B00000000, so it resets Y0-Y7. The MOVK1K2Y0 instruction sends 1 to K2Y0. The binary representation of 1 is B00000001, so it sets Y0 to 1, rather than setting all of Y0-Y7.
[12] When I input T1K20 in the ladder diagram, it displays "Soft component settings are incorrect". What does this mean?
A: The error message "Soft component setting incorrect" when inputting T1K20 in the ladder diagram is because there is no space between T1 and K20. There's no set number of spaces, but at least one space is required. The correct input method is: OUTT1K20. Note that there must be spaces between OUT and T1, and between T1 and K20. When inputting timer instructions, also be careful not to confuse the letter 'O' with the number '0'.
[13] For example, if X001 controls T5 and T5 has a delay of 50 seconds , does X001 need to be turned on for 50 seconds before T5 will act? Or is it enough to just turn on the T5?
A: X001 needs to be on for 50 seconds before T5 will activate. This is because X001 is the timer's driving condition, while T5 is a general-purpose timer. When the driving condition X001 is deactivated, the timer will reset and stop counting.
[14] I have an FX1N-40MR-001 PLC. The output terminal (Y side) has several COM terminals: COM1 , COM2, COM3 , COM4, and COM5 . How do I use them? Which Y terminals do they correspond to?
A: Because the output loads include contactors, relay coils, solenoid valve coils, indicator lights, horns, etc., the power supply characteristics of various loads may be different. In order to accommodate different load power supplies, the PLC divides the output terminals into several groups. The load power supply of the same group of ports is the same, and the ports of different groups can be connected to different power supplies.
The FX1N-40MR has a 4-point common terminal, meaning each of the four output points shares a common terminal. This is called a 4-point common terminal. The correspondence is as follows: COM1 is the common terminal for Y0-Y3, COM2 is the common terminal for Y4-Y7, and so on.
[15] What is the purpose of those black dots on the input/output terminals?
A: The black dots on the input/output terminals are empty terminals left to fit the overall structure of the PLC. They are not internally wired and are useless terminals that do not require any wiring. Empty terminals should not be used as wiring terminals; doing so will interfere with the PLC.
【16】What is the programming cable model for the FX series PLC?
A: The programming cable for the FX series PLC is either SC-09 or USB-SC09-FX. SC-09 is for connecting to the computer's serial port. USB-SC09-FX is for connecting to the computer's USB port.
【17】What does "D<=D150H0" mean in Mitsubishi PLC?
A: [D<=D150H0] is a contact comparison instruction. The "D" in front indicates that this instruction is a 32-bit contact comparison instruction. It compares whether the value of the 32-bit number (D151, D150) is less than or equal to 0. If the condition is met, the contact is closed; otherwise, the contact is opened.
【18】What does [D<=D108C251] mean?
A: [D<=D108C251] is a contact comparison instruction. The "D" in front indicates that this instruction is a 32-bit contact comparison instruction. It compares whether the value of the 32-bit number (D109, D108) is less than or equal to the current value of the counter C251. If the condition is met, the contact is closed; otherwise, the contact is opened.
[19] In Mitsubishi PLC programming, shouldn't the set and reset instructions be used together?
A: In Mitsubishi PLC programming, set and reset instructions do not necessarily have to be used together. Only the set instruction can appear, or only the reset instruction can appear, or they can be used in pairs.
[20] How do I replace the damaged X and Y points in a Mitsubishi FX2NPLC?
A: Damaged X and Y points can only be replaced with spare, working X and Y points if the PLC has them. When replacing them, first, modify the wiring of the external devices accordingly. Second, use the find and replace function of the programming software to find and replace the damaged X and Y points with other unused, working X and Y points. This ensures the program runs normally.
[21] If the external input signal X0 is input 10 times in 1 second, is it necessary to use a high-speed counter?
A: Whether a high-speed counter is needed determines the PLC's scan cycle. The frequency of the counter's input pulse signal cannot be too high. If more than one pulse signal is input within a scan cycle, the remaining pulse signals will not be counted by the counter. This will cause inaccurate counting. Therefore, there are certain requirements for the frequency of the counter's input pulses. Generally, the pulse signal period should be greater than twice the scan cycle to ensure that no counts are missed.
When the external input signal X0 is input 10 times within 1 second, the PLC's scan cycle should ideally be within 50ms. If it exceeds 100ms, it is best to use a high-speed counter.
[22] How many input signals can the FX2N series PLC ordinary counter respond to per second?
A: The maximum number of input signals that the PLC can respond to per second determines its scan cycle. The calculation formula is: 1000 ÷ scan cycle (ms) = maximum frequency of the input signal. To ensure that counts are not missed, the period of the pulse signal should ideally be greater than twice the scan cycle.
[23] In the following program
(MOVPK2D0)
(MOVPK4D1)
(DMOVD0D2)
The program's third line, below D0 and D2, shows the number 262146. How did this number come about ?
A: Because (DMOVD0D2) is a 32-bit transfer instruction, this instruction transfers the data from (D1D0) to (D3D2) . The result of executing the previous two transfer instructions is that D0 is K2 and D1 is K4. In fact, the internal binary number of D0 is B0000000000000010 , and the internal binary number of D1 is B0000000000000100. Therefore, (D1D0) is actually B00000000000001000000000000000100000000000010 . The decimal number corresponding to this 32-bit binary number is 262146.
[24] When applying the master control command MCN0M100, how should the N0M100 contact on the left bus be input?
A: The N0M100 contact on the left busbar does not need to be manually entered. When the programming software is in write mode, the contact is not present on the left busbar. Simply switch the mode to read mode or monitor mode to make the contact appear automatically.
[25] Why can't the programming software on the computer communicate with the Mitsubishi PLC? How should the communication cable port be set?
A: There are several reasons why communication might fail: 1. The PLC may not be powered on; 2. The project type created by the programming software is different from the actual PLC type; 3. There may be a problem with the communication port settings; 4. A USB to RS232 cable is being used, but the driver is not installed or is not installed correctly. There may be multiple reasons, and you need to check them one by one. There are two main types of programming cables : SC-09 and USB-SC-09. When using the SC-09, if the computer does not have an RS232 interface, a USB/RS232 converter is required. When purchasing this converter, you also need to install the driver. After installing the driver, the virtual RS232 port number of the converter will appear in the computer's Device Manager, such as COM4. This port number should be selected for downloading and uploading during programming.
[26] Which programming software is compatible with Mitsubishi PLCs?
A: FX-GPWIN is only suitable for programming FX series PLCs; GX-Developer is suitable for programming FX , Q , and A series PLCs; GX-WORK2 is suitable for programming FX , Q , and L series Mitsubishi PLCs.
【27】How should I input the contact comparison instruction [<=D10K100]? Why can't I input it?
A: To input the contact comparison instruction, you can directly type LD<=D10K100 on the keyboard. Note that there is no space between LD and the <= symbol, but there is a space between the <= symbol and D10, and between D10 and K100. Also note that if the contact comparison instruction is a 32-bit instruction [D<=D10K100], then you directly type LDD<=D10K100 on the keyboard. Note that it is LD followed by D, not DMOV or other function instructions which are preceded by D.
【28】What are K2M0 and K2Y0 in the instruction [MOVK2M0K2Y0], and what does this instruction mean?
A: K2M0 and K2Y0 are combination bit elements. K2 represents the number of groups of combination bit elements, with K2 representing two groups. Each group is a four-bit element, so two groups are 8 bits. Therefore, K2M0 represents the eight bits M0-M7, and K2Y0 represents the eight bits Y0-Y7. The instruction [MOVK2M0K2Y0] transfers the binary data from K2M0 to K2Y0. In fact, it controls the output state of Y0-Y7 through the binary bits of M0-M7.
[29] Why is the ERR light on my Mitsubishi PLC always red?
A: A red PLCERR light indicates a fault, which could be a hardware or software malfunction. You can connect the PLC to the programming software and then use the "PLC Diagnostics" function in the software menu to determine the specific fault.
[30] When opening a project in Mitsubishi programming software GXDeveloper, the message "Project initialization failed" appears. How can this be resolved?
A: When you encounter the "Project initialization failed" error message, you need to completely uninstall the Mitsubishi programming software, delete the registry entries, and then reinstall the software. The method for deleting the registry entries is as follows: 1. Click the "Start" button. 2. Select "Run," then type "regedit," and click OK to open the Registry Editor. 3. Click the plus sign in front of HKEY_LOCAL_MACHINE, find the SOFTWARE folder in the opened folder, click the plus sign, find MITSUBISHI, right-click, and delete the folder. If deleting this folder doesn't work, open HKEY_CURRENT_UESR under SOFTWARE, find MITSUBISHI, and delete it. If deleting the registry entries still doesn't solve the problem, it is recommended to reinstall the operating system.
[31] What should I do if clicking setup does nothing when installing Mitsubishi GX Developer software?
A: If double-clicking setup during the Mitsubishi GXDeveloper software installation doesn't produce any response and the icon doesn't appear, you can try using 360 Security Guard to perform a system check, speed up the process, and clean up junk files. In Task Manager's "Processes" tab, end any processes consuming memory, and then restart your computer. If the problem persists after these steps, reinstalling the operating system is recommended.
[32] Why is there no icon on my desktop after I installed GXDeveloper software, and no icon for the simulation software either? Does this mean the installation was unsuccessful?
A: After GXDeveloper software is installed, the shortcut icon will not automatically appear on the desktop. You can go to Start - All Programs - MELSOFT, find GXDeveloper, right-click and send it to the desktop as a shortcut. The icon will then appear on the desktop. Simulation software does not have a separate icon; it is integrated into the programming software. The "Ladder Logic Test Start" icon in the software is used to start/stop the simulation.
[33] What load can the transistor output of a Mitsubishi PLC drive? Can it be directly connected to a relay? Is a protection device required? Can it directly drive a solid-state relay?
A: The maximum load capacity of a PLC with crystal output is about 0.5A . Solid-state relays can be driven by themselves. It depends on the type of relay. If it is a 24V intermediate relay, it can be driven.
[34] Why is it said that PLC systems have high reliability and strong anti-interference ability?
A: In terms of PLC hardware design, to improve anti-interference performance, optocouplers are used for both digital inputs and outputs, and electrical isolation is achieved between the internal and external circuits of the PLC, effectively eliminating the impact of external electromagnetic interference on the PLC's internal circuitry. Furthermore, the PLC's power supply lines and I/O loops are designed with multiple filtering circuits, such as LC filters, RC filters, and digital filters, to reduce the impact of high-frequency interference. These hardware design features give the PLC strong anti-interference capabilities and high reliability.
【35】What is the result of the octal number 35 + 47 in octal? What is it in decimal?
A: The result of 35 + 47 in octal is 104 in octal and 82 in decimal. Octal numbers only range from 0 to 7, and carry over to the next decimal number when they reach 8. That is to say, 10 in octal is 8 in decimal, 11 in octal is 9 in decimal, and so on.
[36] Can the FX1s-20m be expanded with modules? How are the input and output port numbers defined for expansion modules? For example, is X13 followed by X14?
A: Mitsubishi FX1s series PLCs only have basic units ; there are no expansion units or modules for extended I/O. The input/output port numbers of expansion modules should be used sequentially and cannot skip numbers. X13 is followed by X20, not X14.
【37】How to understand 16-bit and 32-bit operations?
A: Data registers participate in operations using 16 bits, because each Mitsubishi data register is 16 bits. To perform 32-bit operations, two adjacent data registers, such as B0 and B1, must be used to form a 32-bit operation. B0 is defined as the lower 16 bits (lower bits), and B1 as the higher 16 bits (higher bits). The sign bit is located at the highest position of the higher bits, B31, called the sign bit. The 16-bit operation involves addition, subtraction, multiplication, and division using 16-bit data. Similarly, 32-bit operations involve 32 bits.
[38] How to use the END instruction for segmented debugging when debugging a program?
A: The END instruction in PLC is the end instruction. When debugging a program, you can insert the END instruction after each program segment and debug segment by segment starting from the first segment. After debugging, you must delete the END instruction in the middle of the program. This method is also very useful for debugging the program.
[39] Teacher, what is the relationship between the ladder levels and the lines of code in a ladder diagram? Is each line of code one ladder level?
A: A ladder run is a logical unit in a ladder diagram program. A ladder run can contain multiple rows and columns, and all ladder runs are numbered. Therefore, the statement that one line of program is one ladder run is incorrect.
[40] Are the SET and RST instructions function instructions?
A: SET and RST are basic logic control instructions, not function instructions. Basic logic instructions are mainly used for processing switch signals, while function instructions can be used for data processing, including data transmission, transformation, calculation, and program flow control. In addition, function instructions can also be used to handle data transmission and control between the PLC and external devices.
[41] Why can't I transfer K59926 to D0 using Mitsubishi programming software GXDeveloper, but it works when I change it to K29926?
A: Data register D is a word element. The maximum value of the data it stores is K32767. Transferring K59926 to D0 cannot be done because K59926 is greater than K32767, exceeding its maximum value. However, K29926 is less than K32767, so changing it to K29926 will allow the data to be transferred.
[42] When saving the program to the computer, how should the "Project Name Settings" field be filled in?
A: When you save the program to your computer, you can name the "Project Name Settings" field yourself. For GXDeveloper, you only need to enter the project name, while for GXWORKS2 software, you need to enter both the workspace name and the project name.
[43] Why did “Start” appear at all XO contact positions on the ladder diagram after I annotated “Start” at contact XO? Is it possible to annotate different positions of XO?
A: You cannot add different comments at different locations on the XO. If you comment "Start" at the XO contact, then the corresponding comment for X0 is "Start". Once defined, it is essentially a unique comment, so "Start" appears at all XO contact locations.
[44] Can the comparison instruction (LD=) in a Mitsubishi PLC compare floating-point numbers?
A: No, there are specific instructions for floating-point comparison.
[45] Can the D register of a Mitsubishi PLC store the letters NBAG?
A: Yes, it can be stored in ASCII code format.
[46] When editing a PLC program (write mode), if I modify the original program, a new line keeps popping up automatically, making it impossible to modify the original program. I have to delete the original program and rewrite it. To give a simple example: the normally open contact of X0 outputs Y0. I click Y0, a modification menu pops up, I change it to Y1, and then click OK. It automatically outputs Y0 in parallel on the next line. The same thing happens with other function instructions; this is too cumbersome. What settings are causing this problem?
A: It's because "Insert mode" was used. If you've used it, just press the "Insert" key on your keyboard again to restore it.
[47] Can the FXIN-60MR and FX2N-48MR be combined?
A: The FX series PLCs do not have a "multi-CPU system". Different FX PLC models can be connected in an N : N network via an expansion board with a 485 communication expansion interface. For detailed communication methods and selection wiring, please refer to the "FX Series Micro Programmable Controller User Manual (Communication Section)".
[48] What should I do if I forget my login keyword?
A: If you have a backup program, you can first clear the PLC memory and then rewrite the parameters and program.
[49] In the Chinese version of GX-DEVELOPER's software component list, why is there an ERR symbol?
A: Because it's Chinese software, this doesn't mean it's wrong; it means the source and destination are not paired.
【50】Could you please explain the difference between file registers and general-purpose registers?
A: File registers are convenient for storing pre-determined values (such as product inspection specifications). Ordinary registers, except for their holding areas, have all their contents cleared when the PLC is powered off. Therefore, they are generally used as temporary storage areas.
