Delta RMC151 User Manual
Page 700
RMC70/150 and RMCTools User Manual
Use the following RMC parameters:
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1. Set the VC2124 current range to ±20 mA.
2. Set the Output Scale to 4 V/100%.
3. Set the Output Bias to 6 V.
4. Set the Output Limit to 4 V (this keeps the output from going below 4mA).
Inverting the Output
If a positive voltage makes the system move the wrong direction, you will need to invert
the output. To do so, do steps 1-4 above, but set the Invert Output Polarity bit and set
the Output Bias to -6 V.
The mathematical reasoning is as follows:
After setting the VC2124 to ±20 mA, the next step is to scale the ±100% PFID output to
2-10V (the VC2124 will then convert the 2-10 V to 4-20 mA). Use the equation y=mx+b,
where
y = 2-10 V range
x = ±100% range
m = Output Scale [V/100%]
b = Output Bias [V]
To calculate the Output Scale and Output Bias:
Output Scale = m = (y1 - y0)/(x1-x0) = (10-2)/100 - (-100)) = 8[V]/200[%]
Output Scale = 4 [V/100%]
Output Bias = y1 - m * x1 = 10[V] - 4[V/100%] * 100[%]
Output Bias = 6 [V]
For different output ranges, use the same method to calculate the parameters.
Wiring
VC2124
Fuse 24 VDC input with 5A maximum, UL-listed, fast-blow fuse. One fuse suffices for up
to 10 VC2124s. For maximum protection, use one 500mA fuse per VC2124.
For noise immunity, use twisted, shielded pairs for all connections (twisted pair with
overall shield is acceptable). For best noise immunity and CE compliance, keep wires from
the RMC to the VC2124 as short as possible and less than 98 ft (30 m), and place ferrites
on all cables as close to the VC2124 as possible. Sample ferrite part numbers from
Steward: 28A2029-0A0 or 0A2, 28A5131-0A2, 28A0593-0A2, 28A0807-0A2, 28A3851-
0A2, 28A2024-0A0 or 0A2.
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Delta Computer Systems, Inc.