GRT Avionics

Guys,
I recently calibrated my altimeter on my EFIS HX dual display using instructions in Chapter 9, section 9.1.1 of the user manual. I'm on EFIS SW version 6c, and AHRS SW version .43. I have a dual AHRS system.

I have a difference in altimeter readings between the two EFIS displays that I'd like to correct. In trying to use the Altitude calibration procedure on the 2nd EFIS (MFD), I switch to AHRS2 on the bottom menu, and initiate the calibration to (Initiate) ON...but nothing happens. The display just goes back to Altimeter - Calbration OFF in the calibration setting.

Anyone run into this? What am I doing wrong here? The same sequence of process steps worked fine when calibrating AHRS1 on EFIS1.

Thanks,
Howard
GlaStar, N19HL

This is usually caused by a problem with the output from one of the EFIS screens to the AHRS. Only one screen can have an output wire to the AHRS, and usually in a multi-screen system, the first screen controls AHRS 1 and the second screen controls AHRS 2. You can try turning on the calibration from each screen to see if one of them can do it. If none of the screens can activate the altimeter calibration, make sure one of the Serial Outputs is configured for that AHRS on one of the screens. If the serial port is configured properly, check the output wire from the screen to the AHRS.