Myles Sheehy

This is the full program. tested circuit today and it works. let me know what you think! test1.ACD

the progrram i posted was loded from my computer ,which is not setup for the plc in college so it wont let me setup the correct module.the counter counts up to 360 then resets. ill have a look into the peridic task. i'll load up the program i used to run the circuit tomorrow from the computer in college. thats all setup for the analog output module.

Ok, I got it. I used a different method from what you guys were saying. i figured out that if i used the 2-D array i would not be able to adjust the frequency. so i decided to use a counter to count from 1 to 360, the output of the counter went to a math function (deg to radians) then to a trig function (convert RAD to SIN) then a multiplier (x10) so the output voltage would be between 0v and 10v. that was phase one. second phase i i used a addition function, i added 2.09 RAD ( which is 120 deg) to the result from the deg to rad. then this result to a sin function then to a multiplier. phase three was done the same way as phase two, but i added 4.18 RAD (240 deg) to the result . After testing this program using an oscilloscope, the output was three sin waves, each wave was seperated by 120 degrees. Thanks for all the help!

Ok, so far i've been reading about the FFL and FFU. from what i've read they seem to be the ones i need to use as they will copy the values from the array to the FIFO and then unload them. ive also been looking at the COP and FSC functions. one problem... i cant find where to add values to the array?

Hey, ok, so I didn't phrase my problem correctly about running a three phase motor off of a plc the last time. All i need to do is to get an output on the plc of a sine wave and then phase shift (120 deg) the other two. This will demonstrate getting an analog output from the plc. The aim of the project is to become familar with programing an analog output on the allen bradley plc. Im using a 6 channel analog output ( 10v) and the Rslogix5000. Any help with the program would be great. im not asking anyone to do my homework, just some suggestions on the program. Thank alot! myles

Thanks alot for the help! myles

why would we need a single phase of 50hz? could the plc not be programmed to give out the sine wave(s)? the program is only to simulate the motor running. the motor wont actually run. the only thing it will do is that the rotor will expierence a force (the three phases ) being run off the plc. i am using three seperate circuits (op-amps) to runs the phases as i dont want to damage the plc. these will be connected to the outputs on the plc (analog output)

its only to simulate a plc driving the motor. the peak has to be +/-10 v. the frequency in ireland is 50hz.

The motor is about .75 KW and runs off a 240v power supply. i only want the plc to give it +/- 10v at most. my aim is not to drive the motor, just to simulate a plc running the three phases of the motor in the program. i have a small rotor going through the motor and all i want to do is to see, when the program is running that the rotor is experiencing a force (the three phases) the idea is to set up the program to give 3 analog outputs to simulate a sine wave then to phase shift them just like a three phase power would be. The motor is reasonably small and is mounted on a table. I am also using three op-amps because i dont want to damage the plc which has a very small current output (21ma) the software which im trying to program is Rslogix 5000. my knowledge of PLC's is very limited. i have only ever programmed omron and siemens. any suggestions would help, thanks alot, myles

The idea is to set up the program to give 3 analog outputs to simulate a sine wave then to phase shift them just like a three phase power would be. i am using a very small rotor and the idea is to see if the rotor experiences a force which would be the motor running off the PLC. i dont want to drive the motor, just to get the three phases working on time to simulate a three phases of the motor being driven off the plc. The motor is reasonably small and is mounted on a table. I am also using three op-amps because i dont want to damage the plc which has a very small current output (21ma) the software which im trying to program is Rslogix 5000. any suggestions on the program would help. thanks alot, myles

Hey, ok, so I didn't phrase my problem correctly about running a three phase motor off of a plc the last time. All i need to do is to get an output on the plc of a sine wave and then phase shift (120 deg) the other two. This will demonstrate getting an analog output from the plc. The aim of the project is to become familar with programing an analog output on the allen bradley plc. Im using a 6 channel analog output ( 10v) and the Rslogix5000. Any help with the program would be great. im not asking anyone to do my homework, just some suggestions on the program. Thank alot! myles