Read the SITRANS LR100 Radar Signal

Hello everyone!

My current project is to read the level in the tank using level sensor. The analog sensor that I have is SITRANS LR100 Radar and the controller is using PLC SIMATIC s7-1200 CPU 1214C AC/DC/Rly. At first, I just wired the LR100 to the PLC, spesifically in AI built-in, in series with the power supply 24VDC. Previously, I've already setup the LR100 using SITRANS Mobile IQ. Later, the PLC cannot read the analog signal, and then I've just realised in the guide book that LR100 communications using bluetooth, HART, or Modbus RTU. The AI built-in card don't provide the 4-20mA. Then I do some researches to HART module Siemens, and I found6ES7331-7TF01-0AB0is HART enabled module, but can only connected to CPU ET200M. Then SITRANS LT500 also can be connected to LR100, but this isn't I wanted to this project because it's not controlled from a PLC. The I found 6ES7231-5ND32-0XB0 (AI SM1231) that supported 4-20mA and can be connected to 1214C.
The question is, is it possible to add this AI SM1231 module to the PLC, so the signal from LR100 can be read? If no, is there any other alternatives to keep using current PLC?

Regards,

Farkim

Hi Farkim,

the LR100 needs to be connected to an active analog input of the PLC. This means that the 2 wires that provide the signal to the PLC also provide 24V DC to the transmitter. This is possible using the SM 1231 as I understand it.

HART is a superimposed digital signal together with the analog 4-20mA output, so you do not strictly need it in the input module - and it isn't there from what I can see looking through the manual. The LR100 also does not support HART (to get HART on the LR you need to look at the LR110 / LR120). The device will only provide an analog signal to your control system. To program the LR100 you need SITRANS mobile IQ (available from your smartphone App Store) and a smartphone with Bluetooth (5 LE) capability. 

Regards,

Richard Deal | LevelWac