Hello Sapper, So, the external specialists have designed the aperture and the protective devices, so they must have done an assessment against EN 13849 for the modifications to the safety related control systems on the machine, yes? Was the machine originally CE marked? How long ago? They have done their design risk assessments and the operational risk assessments for the modifications to ensure that the machine safety is not compromised? Now technically if the machine is (was) CE marked, then this is now invalid, even if the above has been done. As you have modified both the safety systems, safeguarding and the machine function. So, really, you should undertake a full assessment of the machine against the requirements of the MD. You should at least undertake a full PUWER assessment, and verify the design of the safety systems to ensure that they are adequate. This should really have been done by your supplier and they should provide you with this information, including any updated drawings for the electrical / control systems and a full parts list, along with suitable and sufficient instructions, if necessary prepared in conjunction with yourselves, to ensure that the equipment can still be used and maintained safely. The original safety systems may well have been to EN 954, so you may have a “crossover of standards”, as modifications must be to EN 13849. However, if you have software involved in the system, then you may require a validation to EN 62061, along with a Systema type report. The decision as to which way to go is down to you as a company as it is your risk. Please give more detail then perhaps we can give more details in the answer if you like you can PM.