AC power ('line' power from the US grid) is usually at a frequency of 60 cycles per second (60 hertz). Your PT30C message says it measures a frequency greater than that.
Unless the power to your PT30C is from your generator, there is nothing you can do about it.
Sherm & Terry w/rescues Steve (std Poodle) & Eydie (min Schnauzer)
2015 Jay Flight 27RLS (Camped: 102 nights 2015, 90 nights 2016)
2006 Ford F350 6.0 PSD, Lariat, 4WD, CC, LB, SRW, auto., Camper pkg.