Background:
GE Frame 7EA DLN 1+ with Mark V turbine controller and Cimplicity HMI.

Problem Description:
I have had a dew point sensor fail. The ITDP (dew point temperature) signal has dropped below the -76 degF constant which has caused the alarm DEW POINT SENSOR TROUBLE.

The ITDP signal inputs into a HUMIDV1 Humidity Calculation Big Block. The outputs from the HUMIDV1 block are RHUM (Relative Humidity) and CMHUM (Specific Humidity). These signals are NOT utilized anywhere else in the CSP (Control Sequence Program) of the Mark V turbine controller.

Question:
Since the signals RHUM and CMHUM are NOT utilized in the CSP, I am not concerned about how they will effect turbine operation. I have disabled the process alarm.

HOWEVER I am a curious_one, Has anyone ever seen the above listed signals utilized in some fashion?

 

Curious_One, I maintain 2 7EA's with DLN1. The units were purchased from Calpine after the crash of 2K, and were built as dual fuel. Our great state of CA would never even consider letting us run them on dirty diesel fuel, so we removed all hardware for dual fuel. The original logic for the dual fuel system used the humidity input when running on liquid fuel and water injection for knocking down the Nox value. Our Vaisala dew point sensors also had issues which I removed since they were not being used and all liquid fuel hardware and logic was removed.
We upgraded from MKVI to MKVIe in 2018 and the new application code uses ITDP for new logic for Anti-icing using IBH, so I replaced both of the original Vaisala devices with new. Not sure if the Anti-icing logic will ever be used, but we have good ITDP inputs now. But if your logic doesn't need the inputs why waste your time maintaining the devices that seem to need some periodic maintenance.
My understanding is the ITDP sensor is used for water injection for combustion systems other than DLN and for systems that use foggers.
Hope this helps.

 

Thank you MIKEVI, as usual with GE. If you want the 6 disc CD changer, you have to also get the sunroof. MOON and TUNES package.

 

Curious_One, glad I could help out on this one. I am sure GE has a specific reason why they do, what they do, but sometimes it is not always clear. It helps to keep us curious ones learning something new everyday. Thanks for your contributions and I look forward to comments and help from you in the future.