FYP_First Robot_The Articulated Robotic Arm control by PLC

[mrsolid9]

Hi guys, I'm newbie here. I'm doing my final year project of making articulated robotic arm.

The robotic arm used 4 servomotors for overall operation; three for its joints, and one for the gripping mechanism. This robot expected to differentiate glass and other objects based on reflective theory. And how about PLC programming ?

Please someone help me to find some solutions. Any help is appreciated, thanks a lot

[Tommy]

most PLC's that I'v played with have a scan time of 10ms, not sure they could work with RC servos
using standard I/O's from a PLC, I believe most have PWM output cards available or you could go
serial with something like http://www.seetron.com/sscasd2.html

Tommy

[mrsolid9]

wish you best of luck for your project. and sorry to say that i can't help you in this problem but i am sure that someone in this forum will definitely help you out.
Adam smith
[email protected]
Nitrotek.se

hehe i'm very noob about robot dude..looking for someone can guide me..
thanks 

most PLC's that I'v played with have a scan time of 10ms, not sure they could work with RC servos
using standard I/O's from a PLC, I believe most have PWM output cards available or you could go
serial with something like http://www.seetron.com/sscasd2.html

Tommy

all types of servomotor happen same problem? now i'm using parallax servomotor..
anyway thanks for response dude..

[Tommy]

all types of servomotor happen same problem?

Not sure about ALL servomotors, all the PLC controlled servomotors I'v worked on have a servo
drive board that supplies the power for the motor and gets a control voltage(-10 to 10vdc, 0v=stop)
from the PLC(analog output card needed).

It's my understanding that RC servos are PWM controlled, 1.5ms pulse motor turn one direction
2ms motor turn the other direction.


Tommy

[Soeren]

Hi,

All regular R/C servos (hobby servos) use the same protocol. It's a PDM signal with a repetition rate of ~20ms and a pulse duration from 1ms to 2ms, with 1.5ms being center position.

Unfortunately it's a standard that most servo manufacturers like to break, so the pulse duration may be from ~0.3ms to ~2.8ms worst case, depending on which servo you have.