IFM Electronic Ecomat Mobile Series System Manual page 31

Configurations
Analogue inputs
The analogue inputs can be configured via the application program. The measuring range can be set
as follows:
•
current input 0...20 mA
•
voltage input 0...10 V
•
voltage input 0...30 / 32 V
If in the operating mode "0...30 / 32 V" the supply voltage is read back, the measurement can also be
performed ratiometrically. This means potentiometers or joysticks can be evaluated without additional
reference voltage. A fluctuation of the supply voltage then has no influence on this measured value.
As an alternative, an analogue channel can also be evaluated digitally.
NOTE
In case of ratiometric measurement the connected sensors should be supplied via the same voltage
source as the controller. So, faulty measurements caused by offset voltage are avoided.
In case of digital evaluation the higher input resistance must be taken into account.
Analog
Eingang / Input
Input Filter
Figure: block diagram of the analogue inputs
Analogue inputs ANALOG4...7 (%IW6...%IW9)
These inputs are a group of analogue channels which can also be evaluated digitally.
The configuration can be carried out via the system variable I4_MODE...I7_MODE or, preferably, via
the function INPUT_ANALOG (→ page 248) (input MODE).
If the analogue inputs are configured for current measurement, the device switches to the safe voltage
measurement range (0...32V DC) and the corresponding error bit in the flag byte ERROR_Ix is set
when the final value (> 23 mA) is exceeded. When the value is again below the limit value, the input
automatically switches back to the current measurement range.
ifm System Manual ecomatmobile
U
B
SmartController (CR2500) V05
Function configuration of the inputs and outputs
Referenz-Spannung
Reference Voltage
Spannung
Voltage
31