Siemens S7-200 EM235 Analog Input Tutorial | 4–20mA Scaling & Pressure Control
In this practical tutorial, I demonstrate how to connect a 2-wire 4–20 mA pressure transmitter to Siemens S7-224 PLC using the EM235 analog module.
Topics covered:
4–20 mA wiring (RA jumpered to A+)
EM235 configuration in STEP 7 MicroWIN V4
Manual scaling (6400–32000 to 0–0.4 bar)
Pressure comparison logic
Digital output control with relay (24VDC / 220VAC)
Online monitoring using USB/PPI
Perfect for PLC beginners and instrumentation technicians.