Calculating Scale and offset from RMC100 to RMC150

Forum: Motion Control RMCWin
1

I am upgrading RMC100 to RMC150, and the hydraulic valves and temposonics will remain the same (MDT sensors), units are inches, and some axis are configured as PWM (#4 recirc) and some are Start/Stop.

I want to know how we calculate scale and offset manually from RMC100 program, to use it on RMC150. (I will not have time for full re-calibration)

I was reading the RMC help section, and found out this formula for manual conversion

Position scale(pu/counts) = 1 / [Calibration number (us/pu) 120mhz * # of recirc]

How to calculate the calibration number ? (is it the transducer gradient, 9.012 us/inches ?)

I understand # of recirc is 1 for start/stop, and for PWM is #4 (for my project)

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And also, this blanking period, i should use the same value for RMC150 ?

End

Thanks

2

Are the RMC100 position units inches or thousandths of inches? For example, if an Actual Position value of 1000 equals one inch, the units are thousandths of inches, which is most common for the RMC100. I will assume thousandths of inches.

I will also focus on converting the scale from the RMC100 to the RMC150. That means we don’t need the gradient and recircs, which are used for calculating the scale.

The RMC100 actual position is calculated as:

Act Pos = Counts x Scale / (32768 x Prescale divisor)

The RMC150 is simpler:

Act Pos = Counts x Scale

Therefore, the corresponding RMC150 scale would be the RMC100 Scale / (32768 x Prescale divisor).

If the RMC100 units are thousandths of inches, then it also needs to be divided by 1000.

Because the MDT card is the same, I believe the counts will be the same between the RMC100 and RMC150. This would not be true of the RMC75 or RMC200, which would necessitate further calculation factors.

So in your case, the RMC150 scale for Axis 4 should be:

30300 / (32768 x 4 x 1000) = 0.0002311707

The offset should be very simple. In the RMC100 Axis 4, it is -4945, which is probably -4.945 inches, which is what you should enter for the RMC150.

The blanking period usually doesn’t matter unless you have an ancient sensor.

I don’t do this conversion very often and I find the RMC100 scaling painful, so my analysis should be double-checked for errors.

-Jacob

4

I see I didn’t answer this question: “How to calculate the calibration number ? (is it the transducer gradient, 9.012 us/inches ?)”

Yes, the calibration number is the gradient.