Applies To:
  • CitectSCADA 3.00

I get driver error 0x10500 when I used the KE500 protocol with a SLC 5/x via a 1747-KE module. 

If the KE500 protocol talks directly to the SLC 5/03 CPU via the RS232 port the maximum request size is 1888 bits, but the maximum request size when reading data from a SLC 5/x via a 1747-KE module is 768 bits (96 bytes). The PLC will return driver error 0x10500 if more than 768 bits of information is requested.

The user have to supply two addresses when using the 1747-KE module, the first one for the 1747-KE module and the second for the PLC. The KE500 driver have been modified so that if these two addresses are different then it limits the maximum request size to 768 bits.

You would also get the driver error 0x10500 if you set MaxPending to greater than 2. The default MaxPending for the KE driver is now set to 1. This will not reduce the performance of the driver if it is connected directly to the CPU. The direct connection is three to four times faster than that via the 1747-KE module over the same baud rate.

The SLC 5/02 CPU may return driver error 0x11000 instead of 0x10500 for this problem. Setting MaxPending to 1 will also fixed the problem of others bits in a word being changed when writing to one bit in a word.