Simulation hardware is mandatory if you implement Input or Output blocks (i.e. AI, AO, DI, DO, etc). This control switch must be physically located on the device, for instance a button, a local menu option using keypad, a jumper, a dip switch.
Write protection via hardware is optional.
For testing purposes, it is recommended to attach wires to access the Simulation and Write Protection hardware. This enables the use of an Automation Tool Kit for continuous automated testing of the device.