We are querying some epoch times via Modbus/tcp, and are experiencing some unexpected behavior:
modbus register (a double word, 2 input registers) contains: 1551356992;
data point as 4 byte signed integer, interprets the value differently as 1551302656 with plain formatting, but displays "Jan 18, 1970 14:55:02" when using date/time formatting;
further, another register contains the value 0; data point interprets correctly as zero, but displays "Dec 31, 1969 16:00:00".
No doubt serious pilot error here, but I'm at a loss to make any sense of it.