Festo IFB11-03, Electronic Manual

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B. Accessories
B−18
Festo P.BE−VIFB11−03−EN en 0503g
Analog value representation of input signals
The analog input values are prepared in a 16 bit data format.
The resolution of the analog inputs is 11 bits for current and
12 bits for voltage signals.
Current input (11 bit)
Nominal values
Input
value
inmA Units High byte
B15 B14 B13 B12 B11 B10 B9 B8
MSB
Low−Byte
B7 B6 B5 B4 B3 B2 B1 B0
LSB I/O MUX MUX MUX
ţ
19.992 4094 1 1 1 1 1 1 1 1 1 1 1 0 0 x x x
12.000 2048 1 0 0 0 0 0 0 0 0 0 0 0 0 x x x
4.078 2 0 0 0 0 0 0 0 0 0 0 1 0 0 x x x
Ţ
4.000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 x x x
MSB = most significant Bit LSB = least significant Bit
I/O = Direction control bit MUX = Multiplex bits for channel selection
With the current inputs, the 11 bit wide analog value is ex
panded by factor 2 to a decimal range of 0... 4094. This en
sures that uneven (1, 3,... 2047) decimal values are not out
put. Bit 4 (LSB) always remains 0.
With this expansion the value range of the current inputs is
equal to those of the other analog channels (12 bit).