BTW Our project to simultaneously record GPS data and rad air &

water

temp data has been delayed a week or two. The GPS turned out to be
a Chatty Kathy hogging RS232 time so we need a way to disconnect

it

and reconnect it once every couple of seconds. Turning the
power off & on is not a good idea as it takes the GPS
awhile to recover.

Anybody know of a good quad CMOS analog gate that will work
with RS232 signal levels (+/- 12 Volts) ?

Paul Lamar

The MAX243 is a nice RS232 tranceiver that runs on 5V.
I measured the air temp rise on the oil cooler & right side rad last

week.

~ 40 - 45 on the oil cooler & 43 - 48 on the rad. Depending on power

setting

& climb or cruise condition.  Much smaller range than I expected but

it did

confirm my suspicions that a 10 degree rise would be far lower than

optimum.

Will be interesting to see how Ed's temps compare.

Tracy Crook
tcrook@rotaryaviation.com
www.rotaryaviation.com

I'll check out the MAX243 Tracy. Thanks.

Paul Lamar

Looks like MAX243's are RS232 voltage levels in/out inverters with TTL

in/out.

We need RS232 voltage levels both in & out and buffers.
The data sheet is not clear on the MAX 245. Are those RS232 voltage
levels both in & out? I could use two inverter gates in series to make

buffers.

Paul Lamar

Also I forgot to mention the MAX 243 is not tri state.
Turning the whole chip on and off might work but more
circuitry.

Paul Lamar

Paul

Check out Smart Switch / Port Combiners from B&B Electronics
Might save you a lot of work.

http://www.bb-elec.com/product.asp?sku=232SS2&PathId=44&altsku=smartswitchch
art

It even runs on 12 VDC!

Regards

Erik

OK Erik. Thanks.

I hate to use this sledge hammer approach shown here but I got these chips
in stock and can wire wrap them up in a day or so.

Paul Lamar
 
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