PI E-727 - Page 89

User Manual
E727T0005, valid for E-727
BRO, 2019-06-28
Physik Instrumente (PI) GmbH & Co. KG, Auf der Roemerstrasse 1, 76228 Karlsruhe, Germany Page 89 / 240
Phone +49 721 4846-0, Fax +49 721 4846-1019, Email info@pi.ws, www.pi.ws
So you have to send
SPA 4 0x02000200 50
SPA 4 0x02000300 0.7
to adjust the GAIN and OFFSET parameters for input signal channel 4.
Example 2:
Only positive input voltages are to be used, i.e. the range is 0 V to +10 V.
MinNormalizedValue = 0
MaxNormalizedValue = +100
GAIN = (120 - (-20)) / (100 - 0) = 1.4
OFFSET = 120 - 1.4 * 100 = -20
ScaledValue = -20 + 1.4 * NormalizedValue
Send:
SPA 4 0x02000200 -20
SPA 4 0x02000300 1.4
Example 3:
Positions with positive sign shall correspond to positive input voltages, and positions with negative
sign shall correspond to negative input voltages.
The positive input voltage ranges to +10 V.
Then, the following is valid provided that the absolute value of the negative positions will never be
greater than the positive positions.
MinNormalizedValue = 0
MaxNormalizedValue = +100
GAIN = (120 - 0)) / (100 - 0) = 1.2
OFFSET = 120 - 1.2 * 100 = 0
ScaledValue = 1.2 * NormalizedValue
Send:
SPA 4 0x02000200 0
SPA 4 0x02000300 1.2
Note that these OFFSET and GAIN values would also be valid if axis 1 had a travel range of 0 to
120 µm and if there were only positive input voltages to +10 V.