eWON General Reference Guide - Esco Drives & Automation

General Reference GuideIO Servers Configuration5.10.2.3.2 PT100 input AI5 and AI6These two entries measure a Resistance value in Ohm.AI#Ohm0 162.134095 79.625As you can see, the slope is negative, and if you need to read the Tag value converted in Ohm, you can set a factor of -0.02014774 = -82.505/4095 with an offset of 162.13.Figure 94: Tag’s configuration: reading the tag value in OhmsIf you need to convert into °C: temperature = AI * (-0.0523311) + 161.376.The default range of PT100 in eWON is -50°C to 150°C.Full range of ADC is: -52.92°C to 161.376°C (79.625 Ohm to 162.13 Ohm).Note:• eWON 4002 models prior to S/N 0517-xxxx-89 have a PT100 range from 0°C to 131.9°C and must apply the following formulas:Ohm = IOValue * (-0.012402) + 150.8°C = IOValue * (-0.0322) + 131.9• eWON 4002 models from S/N 0517-xxxxx-89 to S/N 0521-xxxx-89 have a PT100 range from -56°C to 151°C and must apply thefollowing formulas:Ohm = IOValue * (-0.0195068) + 158.2°C = IOValue * (-0.050677) + 151.2RG-001-0-EN ver 1.5 eWON® - 20/03/2009 - ©ACT'L sa Page 122