Input 0; Output 4 - Festo CPX-4AE-4AA-H Operating Instructions Manual

Commissioning
Actual value
0 ... 20 mA
< 0 mA
Tab. 37: Range of values for fixed data format (input 0 ... 20 mA)
7.5.5 Input 0 ... 20 mA - scalable data format
– Measuring range 0 ... 20 mA
– Scalable data format -32768 ... 0 ... 32767
– Scaling above the lower and upper critical limit
– Use of the critical limits for diagnostics
– Conversion of the current values 0 ... 23.52 mA (for sufficiently scaled data range)
– Overflow or underflow for values outside of the data range (> 32767 or < -32768)
– No underflow: actual values < 0 mA not possible (reverse polarity protection)
– Conversion of analogue actual value to the digital input value:
Digital input value = actual value x (upper critical limit - lower critical limit) / 20 + lower critical limit
Actual value
> 23.52 mA (hysteresis < 23.42 mA)
0 ... 20 mA
< 0 mA
Tab. 38: Range of values for scalable data format (input 0 ... 20 mA)
7.5.6 Output 4 ... 20 mA - fixed data format
– Value range 4 ... 20 mA
– Data format not scalable
– Current value output 0 ... 22 mA
– Current value output in case of overflow (> 22 mA): 22 mA
– Current value output in case of underflow (< 0 mA): 0 mA
– Conversion of the digital output value to the analogue setpoint value (current value output)
Current value = 4 + 16 x digital output value / 27648
Digital output value
> 31104
31104
27649 ... 31104
0 ... 27648
-1 ... -6912
42
Digital input value
0 ... 27648
–
Digital input
value
32767
-32768 ... 32767
< -32768
Current value output
22 mA
22 mA
> 20 mA
4 ... 20 mA
< 4 mA
Meaning
Nominal range
Underflow not possible:
Reverse polarity protection
Meaning
Overflow
Nominal range, freely scalable
Underflow not possible:
Reverse polarity protection
Meaning
Overflow
End of output range
Overdrive range
Nominal range
Underdrive range
Festo — CPX-4AE-4AA-H — 2021-06b