ST 50 Wind as Repeater for ST 60 System

[H/V Vega]

Guess the title says it all. I need a second wind speed and angle down below - maining to keep dry when its blowing on anchor and I'm chewing me nails down below. Well I do have a few other reasons. In any case found a good st 50 wind inst and poped it into the seatalk line. Both still work but the readings are almost 180 degrees off - port is starboard and the like. I think I need to set the st 50 as a slave unit but cannot find any reference on how to do it. Could use some help here maties. Have a long trip coming up and would love to have them both working.