MVI69-GSC and 18kb Data Stream

RE:MVI69-GSC and 18kb Data Stream

"Streaming" mode is generally more appropriately used for short data bursts at widely spaced intervals. The ladder logic required to handled as much data as you are inquiring about in Streaming mode would have to be very carefully crafted to prevent the lost of data. While it is true that the module's internal port buffer can hold up to 4096 8-bit bytes of data (32768 bits); in streaming mode, it will never be allowed to accumulate that much data before it dumps bytes to the Input Image for the ladder logic to process.

Normally, the module would be configured to look for string terminating conditions of strings with much fewer characters. When you set the port mode to "Streaming" the module will transfer whatever bytes it has in the port buffer every time it gets the chance to send a new Input Image to the ladder logic. This is generally about once every two to three module RPI intervals. The number of byte or bits that will be transferred in any given Input Image cycle depends on many factors, including the Block Transfer Size, Processor Scan time, RPI of the module, etc. This will often be a variable number of bytes and the receiving ladder logic will have to be written to collect and concatenate these partial streams into a total data block. If this is not done correctly, then data will be lost. Also, if the data is coming into the port faster than it can be transferred across to the ladder logic, data will be lost.

Before we can say whether or not the module can support that kind of data rate or not, we will need many more details about your application. Before I can effectively answer your questions, I need some additional details about your application. Please send me a copy of the ladder logic you are using in your processor, a copy of the configuration file you downloaded to the module, and, if possible, a sample dataset of the "17kb data flow" you expect to be able to receive with the module. After I have a chance to review that information, I may be able to understand your problem better and make valid recommendations for resolving your issues.

If you care to send the details of your application to us, we can provide more specific recommendations. Please send all further correspondence on this matter to Support@psft.com or to the Technical Support Engineer assigned to your case. Thank you.