Can't get Maestro 18 to work with serial port commands

My maestro 18 works fine through the Command Center(windows 7 or XP), but I can’t get it to work using explicit serial port commands. Device manager shows Command Center(com4) and TTL(com5). I’ve tried both Compact and Pololu Modes using both com ports. When I send a Set Position command, I see the green LED flicker, so I think the Servo Controller is recieving the command, but the servo does not move. The servo can always be turned freely, except after using Command Center. It acts like the servo is not enabled. Do I need to enable the servo or tell the controller the serial port mode before I send the servo controller a command? I’m familiar with using the previous model 390 and have had no issues like this. Thanks for your help!


It sounds like you might not be in the correct serial mode. Under the “Serial Settings” tab in Maestro Control Center, you should have USB Dual Port selected. Also, you should be using the Command Port (COM4) to send serial commands to the Maestro.


You’re a genius JeremyT! Thank you very much! Now can you help me with speed and acceleration? For Set Speed or Set Acceleration, anytime I set the speed high bits = 0 and send a Set Target, the red error LED comes on. I’d like to set the speed to 20 decimal so speed low bits = 20 and speed high bits = 0 but this causes red LED to light. Thanks for any help!

The red LED means you are getting an error. Could you look into the errors tab and look at which error you getting? Could you also post your code?

- Jeremy