TOPIC: gps speed pulse input for ART-120

We have a ART-120 and we would like to use a GPS speed pulse instead of a wheel sensor. Can you tell me which pins of the mini-din port are used for the speed pulse from the Hall-effect sensor? The speed pulse I would like to connect uses a 4.7k pullup to 5 volts. I assume this would be compatible with the Agtron wheel sensor.

We would also like to connect a coverage switch to the ART-120. I understand that this function is done using a momentary switch connected the D-sub 9 receptacle. Could you describe the necessary pins? I already built a converter that takes a on-off signal and does edge detection to convert it to a momentary pulse. I'm using an opto-isolator to provide the open/closed momentary signal to the ART-120.

Hi nascheme,
Your speed sensor should work just fine with the ART-120. Here's the pins you'll need for the mini-din:

pin 3: Ground (brown)
pin 5: +12V power (white)
pin 6: signal (orange)

For the workswitch connection on the D-sub 9 connector, pin 8 is signal, and pin 5 is ground. The momentary switch simply connects pin 5 to ground.

Reid wrote: Here's the pins you'll need for the mini-din:

pin 3: Ground (brown)
pin 5: +12V power (white)
pin 6: signal (orange)

I wired it up yesterday but no luck. I'm using the speed pulse source to feed a Raven 440 as well, maybe the 4700 Ohm pullup is too weak to run them both.

Does pin 6 expect a 5 V signal or would 12 V be acceptable as well? Also, what is the impedance of that pin, could I feed it 12 V without a pullup? My preferred strategy at this point is to use an optoisolator to feed the Agtron it's own 12 V level (i.e. essentially a switch between pin 5 and pin 6). That would eliminate the risk of ground loop problems as well.

Nascheme,

The mini-DIN signal input on our ART-120 monitors is already optically coupled so any open-collector type drive should work. Early ART-120 models (pre-2005) did not have an optocoupler on the inputs, they had a weak 10K pull-up to 5V and a 1K input impedance. Either way, it should work with your 5V based input. If you provide the serial number on the back of the monitor head, we can tell you if it is new enough to have the optocoupler input.

Have you gone through the calibration steps to assign the speed input to the mini-DIN port? You can quickly test the calibration settings by just tapping the signal wire with ground, you should see a non-zero speed on the ART-120 display (in speed mode). You'll of course also have to set the 'circumference' value on the monitor head to the distance traveled per pulse from your speed sensor.

Hope this helps.

Nascheme,
Just a little more info to add, to set up the speed sensor on an ART-120, you want to press the button for speed mode, then hold the up arrow for 3 seconds to change the speed sensor type. There are several options to choose from, which are outlined below:

OFF - no speed sensor, test speed will be used
GND0 - 1:1 ratio on the monitor minidin port
GND1 - 1:1 ratio on splitter fan port
GND2 - 1:1 ratio on splitter aux1 port
GND3 - 1:1 ratio on splitter aux2 port
RDR0 - 32:1 ratio on the monitor minidin port
RDR1 - 32:1 ratio on splitter fan port
RDR2 - 32:1 ratio on splitter aux1 port
RDR3 - 32:1 ratio on splitter aux2 port

Thanks for the quick response. I don't have the serial number handy, it could be an old version since it was a refurbished unit. I think with the information provided I should be able to make it work so thanks for that.

Another question, I see the most recent manual describes options for a on/off work switch on the mini-din port. That would be nicer than using the momentary input on the dsub. Can you provide any details about pin used and the signal expected?