DL205 scaling help

[dginbuffalo]

Back again for some advice. i need to take the output of a PID loop and scale it to 0-600 to send across Modbus to a GS-2 VFD. is there any easy instruction to do this? i try using a MATHBCD box with this expression ((k600-k0) / (k4095-k0) * v2205 . V2205 is the PID output. the result never comes off zero. is it because the division is getting rounded to zero? must be a simpler way.

 

[dginbuffalo]

Bizarre... i tried to use a ANSCLB analog scale box before and it didn't work. Now i tried again and it does?? O well.

 

[bernie_carlton]

LD V2205
MUL K600 - the accumulator will hold a number larger than 9999 ok
DIV K4095 - this divides the total result of the multiplication by 4095. Except for the loss of a fractional part it should be accurate.
OUT Vxxxx

But now I see your note that the value is the output of a PID loop. The input and output parameters for PID loops are in binary, not BCD. Knowing that try this:

LD V2205
MULB K258 (hex value of 600 decimal)
DIVB Kfff (Hex value of 4095 decimal)
OUT Vxxx (this will be a binary value)

If this is a DL250-1 or DL260 you can also try the ANSCLB IBox command.

(I'm obviously too slow.)

 

[dginbuffalo]

Thanks Bernie- yes, i had success with the IBox ANSCLB instruction.