Rockwell Automation T8431 Trusted TMR 24Vdc Analogue Input Module - 40 Channel - Manual (Page 18)

Trusted
TM
Module T8431
Issue 16 Sep 11 PD-T8431 18
3.2.3. Rack 3: AI
The AI board returns the engineering units for the associated field input.
Channel Description
1 Field input channel 1 voltage
2 Field input channel 2 voltage
40 Field input channel 40 voltage
Table 8 Rack 3: Channel Field Engineering Units
The voltage is the median value taken from the triplicated module. Field input current is converted to
voltage using a 250R resistor on a standard field termination assembly (FTA). This AI value may be
used directly or scaled using the IEC1131 TOOLSET conversion tables. The voltage is reported as
1024 counts per volt. To allow easy scaling for 4-20mA inputs, zero volts reports as -1024, one volt
reports as 0, and 5 volts reports as 4096.
Using a 250R field loop configuration the following table represents normal operating values
Voltage Current Engineering Unit
Open
Circuit
-2048
0 0mA -1024
1 4mA 0
2 8mA 1024
3 12mA 2048
4 16mA 3072
5 20mA 4096
Table 9 Rack 3: Normal operating values