In the last post of this thread there are some test results of the response time of the VM110N/K8055N card using DLL versions 4 and 5:
When version 4 of the DLL is used, the VM110N/K8055N card is running in the VM110/K8055 compatibility mode.
In this mode the card is transmitting all the time the input status data to the USB bus.
When the version 5 of the DLL is used, the input status of the card is requested by the PC software. This is why the response time of the functions ReadAnalogChannel, ReadAllAnalog, ReadDigitalChannel, ReadAllDigital and ReadCounter is about 2ms with version 5 and about 1ms with version 4 of the DLL.
The response time of all output functions as WriteAllDigital, OutputAnalogChannel, SetDigitalChannel, ClearDigitalChannel etc. is equal with both DLL versions 4 and 5.
The response time is normally 2ms and about 1ms if the VM110N/K8055N card is connected to the PC via an external USB HUB.
Using the DLL version 4 may cause some latency to the data read. The data sent from the VM110N/K8055N card to the USB bus is fed to a ring buffer in PC.
To avoid the latency, the data have to be read as fast as it is written to the buffer.
The latency problem is avoided by using the version 5 of the DLL.
Please do not put the SearchDevices function to the main loop of the software.
Use it only occasionally to check the card connection.
The original purpose of the SearchDevices was to use it just at the beginning of the program only.
The execution time of the SearchDevices function is about 15ms with DLL version 184.108.40.206 and about 30ms with version 220.127.116.11.
You may also use the Connected function of the version 5 DLL to check card disconnection.
Now also the version 4 of the DLL is modified.
Here is the link to download v18.104.22.168 of the K8055D.DLL:
In this version the SearchDevices will not increase the number of handles.