A computer system that is adapted to communicate with an industrial system, the computer system having: a data collection server that is adapted to receive equipment data from the industrial system and to provide a data stream by pre-processing the equipment data according to a plurality of pre-determined rules; a first uni-directional interface that is adapted to transmit the data stream to one or more further computer systems; a second uni-directional interface that is adapted to receive a data packet from the one or more further computer systems, wherein the data packet comprises a control instruction that allows the modification of at least a particular rule (Rk) of the plurality of the pre-determined rules, wherein the first uni-directional interface is implemented with a data diode and the second uni-directional interface is adapted to receive the control instruction in a first part (125-A) of the data packet and wherein the second uni-directional interface is adapted to receive the first part (125-A) of the data packet in a size that correspond to the amounts of data required to identify the modification of the particular rule (Rk), wherein the size limitation of the first part (125-A) has an equivalent limitation by the second uni-directional interface that is adapted to receive the first part (125-A) in a maximum size, the computer system being characterized in that the maximum size of the first part (125-A) depends on the type of control instruction, wherein there is a size constraint for one rule modification in a single control instruction, or a size constraint for a given number of rule modifications in a single control instruction. a data collection server that is adapted to receive equipment data from the industrial system and to provide a data stream by pre-processing the equipment data according to a plurality of pre-determined rules; a first uni-directional interface that is adapted to transmit the data stream to one or more further computer systems; a second uni-directional interface that is adapted to receive a data packet from the one or more further computer systems, wherein the data packet comprises a control instruction that allows the modification of at least a particular rule (Rk) of the plurality of the pre-determined rules, wherein the first uni-directional interface is implemented with a data diode and the second uni-directional interface is adapted to receive the control instruction in a first part (125-A) of the data packet and wherein the second uni-directional interface is adapted to receive the first part (125-A) of the data packet in a size that correspond to the amounts of data required to identify the modification of the particular rule (Rk), wherein the size limitation of the first part (125-A) has an equivalent limitation by the second uni-directional interface that is adapted to receive the first part (125-A) in a maximum size, the computer system being characterized in that the maximum size of the first part (125-A) depends on the type of control instruction, wherein there is a size constraint for one rule modification in a single control instruction, or a size constraint for a given number of rule modifications in a single control instruction.