Applies To:
  • CitectSCADA 5.xx, 6.xx
  • CitectHMI 5.xx, 6.xx

Since upgrading Premium firmware from PL7 to Unity, error 0x105 is observed when reading and writing to the following registers:

%I, %IW, %Q, %QW.

Details of Driver error:

105 ERR_NEG_CONFIRMATION Device could not execute request.


Substantial changes have been made to the Unity firmware. This includes a rationalisation of the Uni-TE requests supported by the Premium Unity processors.

Currently the only registers supported by the Premium Unity processors are:

Read internal - %M
Read internal word - %MW
Write internal bit - %M
Write internal word - %MW

It is highly recommended that users wanting to communicate with the Premium Unity processors use either the Modnet protocol, or OPC protocol.

For more information about which Uni-TE requests the Premium Unity processors support, please consult the Schneider FAQ entitled:

"Which Uni-TE requests are supported by Premium Unity PLCs?" or Resolution Number: 167403