[S7] When trying to write to a S7 device and writing is not explicitly enabled, the PLC will respond with an error code

[ottlukas]

The S7 will respond with:

• Error Class: 0x83
• Error Code: 0x04 

if the user tries a write request and this is not explicitly enabled, we can definitely handle this in a nicer way.

To fix the problem, you need to select the PLC in TIA, go into the Properties dialog, select "Protection". You will probably notice there's an Access Level Table, but you need to scroll down (even if it looks as if there is nothing). There check the box in: "Permit access with PUT/GET communications from remote partner...."

Would be cool if we could give our users a hint on this.

Imported from Jira PLC4X-208. Original Jira may contain additional context. Reported by: cdutz.