FX3

[Michael39]

Hi, I am in the middle of writing some code for controlling some variable speed drives using a Mitsi FX3U I want to control the ramp within the PLC. I've tried the ramp fuction but it does'nt work to well. Does any one have any suggestions. I am using a 0-10v as a analogue reference output. Michael.

[Crossbow]

What do you mean it doesn't work too well? Can you describe what it's doing that's not what you expected it to? If you tell us more about what you are trying to accomplish, we can try to help.

[Michael39]

I am using -[ramp D6 D8 D10 K500]- then -[mov D10 D6]- to try an create a smothe ramp in register D10 when I write a new value in D8. The the rate of change slows at the end of the ramp. Michael.

[panic mode]

really? hmmm, i just can't see that happen. i suspect that the parameters are changing before instruction is complete or instruction is not scanned on every scan. could you post your program? you could make your own ramp logic that would do same thing just by counting scans, using timer or whatever.

[FNMdeJong]

The code what you wrote and the explanaition given from you is the correct way it should work. RAMP [s1 s2 d1 n1] s1 = starting value s2 = end value d1 = current value n1 = ramp time so if you move every time the current value to the starting value you decrease the deviation of the ramp, and you keep the same ramp time. This means it starts fast to increase the current value and slows donw to the end value. In theory it will never reach the end value. Only because of rounding it will be reached. See the programming manual under the section 14 Handy instructions function function 67.

[Crossbow]

I hadn't even thought of that one... Nice catch! I was looking at the Ramp instruction, not at his follow-up MOV command.

[Michael39]

Hi, What is funcion 67?

[cauchy]

Function 67 is RAMP function. And you can find this manuel in downloads.