Kepware And SLC

I have a SLC 5/05 that has several float files (F22 - F29) every file contains the maximum number of elements of 256. Kepware OPC Client utility CAN NOT read the first half (ie: F22:0 - F22:127) but CAN read the second half (F22:128 - F22:255) of those files.

I also have float files at F8 (default) F100 and F101. Kepware has no trouble reading the entire range of elements of these float files.

Kepware has no trouble reading integer, binary, timer, counter files.

I have deleted the float files in the PLC using RS Logix 500 and added them back in, re-download to the PLC and it does no good, they still won't read.

I can create and add a new (unused) float file and Kepware can read values in this newly added float file.

I have cleared the CPU memory an reloaded the entire program and the problem is still there.

Anybody got anything?

Wags

When you say can not read, do you mean you get a bad quality reading? Does kepware refuse to accept the addresses when creating the tags? Is the data type in kepware set to FLOAT?

What driver are you using? Will it read these values from another PLC?

Need some more information about this.

Are you getting errors in the server event log relating to those float adresses and if so what are they.

wags said:

I have a SLC 5/05 that has several float files (F22 - F29) every file contains the maximum number of elements of 256. Kepware OPC Client utility CAN NOT read the first half (ie: F22:0 - F22:127) but CAN read the second half (F22:128 - F22:255) of those files.

Wags

Click to expand...

It is my belief that a SLC 5/05 can read handle 256 words in one instruction, a word being 16 bits.
Now you are using a float point which I believe to be 32 bits which means 128 floats is the limit.

Could it be that its reading the first half then immediately reading the second half but in the process over writes first half data.

The driver automaticaly blocks the request accordingly. It recieves and process a request response before sending another request. There shold be a message in server message log if there is any problem requesting the particular registers.