FAQ LensConnect
■Interface
Q. Are there other interfaces besides USB?
- We have products compatible with the I2C interface.
Q. I would like to buy the I2C interface version. Where can I buy it?
- Please inquire here.
Q. Why do you use USB 2.0 and not USB 3.0?
- The communication speed of USB 3.0 is not needed, so we use USB 2.0, which supports a longer transmission distance.
Q. Can multiple lenses be connected using the USB interface?
- Yes, multiple lenses can be connected. However, lenses may not operate correctly if current is insufficient, so be careful about the supplied current.
Q. Are there voltage specifications? What is the power needed to drive the lens?
- Voltage is 5 V ±5% for both the USB version and I2C version. The necessary current varies depending on the product. (The system operates at about 200 to 350 mA.)
Q. Is there any problem if the voltage goes lower?
- The motor may not operate if voltage is too low.
Q. Can the system be controlled from a PLC?
- At present, no.
Q. Can the system be controlled from an FPGA?
- When using an FPGA, it is recommended to use an I2C interface. The system can be operated if controlled according to the procedure indicated in Protocol Documents. (Please download and use the Protocol Documents from here.)
Q. Can the I2C interface version be operated with 3.3 V?
- The system operates with a voltage of 5V, but there is pull-up to 4.7 KΩ on the lens side. If the microcontroller on the control side is not 5V tolerant, consider adopting a voltage conversion circuit.
Q. Are there any other precautions for the I2C interface version?
- Clock stretching may be used in command processing, so support for clock stretching must be provided on the control side. An error will occur if no support for clock stretching is provided. At present, almost all microcontrollers provide support for clock stretching.
Q. What is clock stretching for the I2C interface?
- In I2C communication, the master (PC side) normally makes inquiries, and the slave (lens side) responds. SCL (clock) and SDA (data) are used for communication. Data is sent and received according to clock timing. The clock is controlled by the master, and the slave sends and receives data according to that clock.However, if the slave cannot follow the clock (i.e., if the data or response is not ready), the slave can make the master wait by setting SCL to LOW. This function for setting SCL to LOW is called clock stretching.
Q. Will there be some problem if the USB connection is unstable (chattering)?
- Problems will occur with lens operation. If the connection is temporarily disconnected due to chattering, the communication must be started after reconnection. If the power supply is cut off (instantaneously) due to chattering, initialization will be necessary. Whether initialization is needed or not can be checked with the initialize need bit of each device.
Q. Is there a way to check whether the motor has arrived at a designated
- The Busy signal can be used as one way of actively notifying the control side from the lens side.(This is only supported with the I2C interface version. Busy signal connection is necessary.)With USB, the status can be ascertained by reading the Status1 register.
■Cable
Q. The USB cable is too short at 30 cm. Can it be lengthened?
- Our company doesn’t customize cable lengths, so customers should obtain a USB extension cable on their own.
*Be aware that 5 m is the maximum length with the USB 2.0 standard.
Q. I want to extend the USB cable longer than 5 m. Is there a good way to do that?
- It can be extended by using a USB repeater cable.
Q. Is there a recommended USB extension cable?
- Lengthening distance tends to increase susceptibility to noise, so we recommend using cable with reinforced double shielding as USB extension cable.
■Control / Operation
Q. Is initialization always necessary after turning power on? Is initialization performed automatically?
- Initialization is required after turning on power. It is not done automatically.
For information on the initialization method, see the API Guide / Protocol Guide. (Please download and use the API Guide / Protocol Guide from here.)
Q. Can zoom and focus be operated simultaneously?
- That type of operation is not possible at present.
Q. Is the lens position maintained when power is shut off?
- Generally speaking, the lens position is not maintained when power is shut off. However, with the following products the lens position is maintained even after shutting off power.（VL0826U-MPZ, VL1226U-MPZ, VL1624U-MPZ, VL2520U-MPZ, VL35226U-MPZ, VL5024U-MPZ, VL7531U-MPZ）When power is turned on again, the system is in a state where the address is undetermined, so please always use after initialization.
Q. Is the position maintained after finishing with the LensConnect controller?
- As long as power is supplied to the lens, the position is maintained and also stored in memory.
Q. The screen seems to shake only when the lens is operated in a certain direction. Is something wrong?
- When the lens is driven in a single direction, the screen appears to shake due to correction for backlash in the mechanism. When this correction is ON, position reproducibility is maintained in operation from any position. This function can be turned OFF if the shaking bothers you.
Q. How does the system operate when backlash correction is ON?
- Basically, the system stops at the target address in the direction of decreasing addresses. When stopping in the direction of increasing addresses, the system first passes beyond the target address, and then doubles back and stops at the target address. When stopping in the direction of decreasing addresses, the system proceeds directly to the target address and stops.
Q. I’d like to know: how long is the time until motor operation begins?
- Time from when a command is issued from the control side to when the motor begins moving is about 1.5 ms (reference value).
Q. After initializing, a sound is audible even though the motor is not operating. Is something wrong?
- The sound audible from the lens is due to excitation of the motor. Nothing is wrong.The following products don’t make a sound because excitation is not performed when stopping.(VL0826U-MPZ, VL1226U-MPZ, VL1624U-MPZ, VL2520U-MPZ, VL35226U-MPZ, VL5024U-MPZ, VL7531U-MPZ)
Q. During focus (zoom), the motor makes a sound but the lens does not move. The iris is operating.
- Is the USB supply current sufficient? If current is not sufficient, the lens may not operate. Please inquire with us if the system does not operate even though sufficient current is supplied.
■ Program
Q. Lensconnect_Controller does not recognize the lens in the Linux environment.
- Please execute the program with administrator privileges (root).
Q. Are there recommended PC specs for controlling LensConnect?
- There are no specific required specifications. There will be no problem, provided the PC supports USB 2.0.
Q. Are there limitations on the Windows version?
- At present, we are not aware of any information indicating that the system does not work with specific versions. However, it may be impossible to use the GUI with Windows if the .NET Framework version is too old. (Our software uses .NET Framework 4.7.2)
Q. Are there limitations on the distribution with Linux OS?
- At present, we are not aware of any information indicating that the system does not work with specific distributions.
Q. Will the system operate on a single board computer like Raspberry Pi or Jetson, etc.?
- Operation has been checked on Raspberry Pi 4 and Jetson Xavier NX.
Q. I want to download sample programs and the API / Protocol Document. Do I need to register an account?
- We’re sorry for the inconvenience, but you must register a user account due to our company’s system. If there is an issue, e.g., if you can’t register an account, please inquire from our website.
Q. Do you have SDK?
- Sample programs and documents are available. Download from here for use.*You must apply for an account to download.
Q. What development languages are there?
- For Windows: C#, C/C++, and Python. For Linux: C/C++ and Python.
Q. Are sample programs compatible with 32 or 64 bits?
- Windows C# and C/C++ are compatible with both 32 and 64 bits. Linux is compatible with 64 bits. It can support 32 bits by changing the Make file and using the 32-bit library folder. Python is currently only compatible with 64 bits.
Q. Is there a USB dll (library) Document?
- Yes, it can be downloaded at the Silicon Labs website. Download from here and then use.
Q. We’ve written the Position_Value for Focus, but the system does not operate, and the value is not updated.
- Check whether the value written into Position_Value is outside the range between Focus_mechanical_step_Min and Focus_mechanical_step_Max. Values written outside that range are ignored.
Q. Can you provide sample programs with Visual Basic .NET?
- At present, we do not have sample program source available for Visual Basic .NET.
Q. Is there a method of file execution not employing the sudo command using administrator privileges?
- Please create rules by referring to the file here.
Q. There is a link error during compile (make). How should we deal with this?
- Install the library by referring to the file here.
Q. An error occurs when executing the execution file. How should we deal with this?
- Install the library by referring to the file here.