HMI SERVO PROGRAMMER

[sparkysa]

Hi all
I downloded the hmi software and manufactured the serial cable to specification with a 3.3 k resistor but I keep getting an error or noconnect message.
I am tring to program a hitec 5990 servo.
I have looked at all the forum info and believe my port settings to be correct.19200 ,stop bits 2,patity none,data bits 8
I am using a usb to serial interface-Mecer
both my laptop and desktop pc with the same resuls.
I have tried on
has anyone got some suggestions on what im doing wrong ??

thank you for your help in advance
Mike, South Africa

[i-Bot]

What are you using to power the servo ?

[sparkysa]

Hi, Thanks for replying. I am using a four cell RC nicad pack- 1,100mah. I thought of using a lipo 2 cell pack but was worried to damage the circuitry of the servo without a regulator. Do you think I should use a 6V pack?

[i-Bot]

4.8 Volts should be fine.

I did not try the cable, because I already had a different interface. I will try it tomorrow on a 5990.

[Sazabi]

In "Servo" mag (jan 2008) is an article about hmi programmer. As i remember, author had same problem. Only way he could make a connection is when he removed 3.3k resistor from scheme. But it's not save. Problem was in his usb-to-com converter.
Or you can make a completely diff interface as I-Bot sad.

[sparkysa]

Ok. thanks for the feedback i-Bot and Sazabi. Ill try get a different interface then maybe try remove the resistor and not damage the servo.