Issue:

Unable to load a program via USB stick to the HMIS5T

Product Line:

HMIS5T

Resolution:

Recently we have been informed of situations where USB sticks are not working with our HMIs. Through our investigation, it is generally related to USB sticks that are typically a non-famous brand (or no name brand). In addition, we have found that usually these sticks are advertised as USB3.0 and are backwards compatible. In reality, we have discovered that they are are not.

When these non-famous brand USB sticks advertise as being backwards compatible, it is not always the case for our HMIs. The USB sticks are marketed to the mass commercial market that uses them for Windows or MAC PCs. Windows and MAC OS are generally a bit more loose when it comes to integrity checks. A few sectors here and there can be bad and the stick will still "work" for the purpose of transferring pictures, document, and other less critical files. However, for an embedded system like an HMI and PLC, data integrity is very important so the checks are stricter. The data is essentially responsible for controlling a machine after all. Life or Death is at stake in some cases.

When the HMI or PLC refuses to accept the USB stick, it is a general sign that the USB manufacture is not following the USB standards strictly and are taking some shortcuts somewhere.

From experience, we have found that brands such as SanDisk, Kingston, and Lexar produce reliable USB sticks. If we are able to find a USB 2.0 stick, these work very well. For USB 3.0 sticks, generally the brand name ones work but some may have issues. In an upcoming release of Vijeo Designer 6.2 SP11, we will improve the USB 3.0 compatibility so that there will be better compatibility.

What we can recommend today is:

1) Format as FAT32

2) Allocation size should be no more than 8192 bytes

3) A USB 2.0 stick is best

4) Stick to a Brand Name USB stick for reliability

In general, this is a hard topic to give an exact answer as there are simply too many USB sticks and too many varying "USB standards" out there.

發佈於: 施耐德電機Taiwan