Rockwell Automation T8840 Trusted Temperature FTA - Manual (Page 8)

Trusted
TM
Temperature FTA T8840
Issue 4 Apr 10 PD-T8840 8
Figure 3 System connectivity using VFTA
For signal conditioning units that provide signals as 4 to 20mA for low to high engineering range, a
conversion is needed because the voltage measured by the module input is not exactly 1 to 5 volts.
EU = ((count/4036.5) – 0.007828) x (HEU – LEU) + LEU
Where:
LEU = Low engineering unit range
HEU = High engineering unit range
Count = Raw value seen by input
EU = Engineering unit value
For signal conditioning units that provide a voltage signal of 1 to 5 volts, no special factors are required:
EU = (count/4096) x (HEU – LEU) + LEU.
VFTA
8842
Temperature
FTA
8840
Temperature
FTA
8840
Temperature
FTA
8840
Temperature
FTA
8840
Temperature
FTA
8840
Typical Configuration using conditioning
Devices with 1 to 5V output Using a VFTA
Up to 8 temperature devices
Analogue
module
8431