Go to Software RSLogix 500 and choose the CPU

First in this case gonna configure "Analog Input Module" go to side in I/O configuration and select one of the Modules AI, for this case will choose 1762-IF4

Now in this example configure Inputs AI 4-20mA select "Adv Config" and then "Analog Input Configuration", for this case the Electrical System in CHILE has Frecuency 50HZ, So select 50 HZ in Filter, if your country has a frecuency of 60HZ you should select 60HZ

Next step and very important is add the function "SCP" Scale with Parameters

As you see in image, we can add a "BIT" tipical, right click and select "Change Instruction Type", after write "SCP" and will appear the block we need...SCP

before to begin to configure this IMPORTANT BLOCK, Let's analyze:

• INPUT For this case will connect here Analog Input/Signal, in this block of example will connect directly since the Sensor to PLC, it means in this block we have the signal 4-20mA from Sensor


• Input MIN You must to consider the Minimum Software value of 4-20mA in this example 4mA => 3277 (information has a lot of source, you can see below a table with parameters)


• Input MAX You must to consider the Maximum Software value of 4-20mA, in Analog mA is by table 16384, all values used in RSLogix 500


• Scaled Min Here we begin to scale Minimum Software Value, in a New Minimum Value assigned by us


• Scaled Max Here we begin to scale Maximum Software Value, in a New Maximum Value assigned by us, remember Max Software value for Current 4-20mA is 16384s


• OUTPUT Final and Scaled Output from the New Value, it means here you have final value scaled and then with this value we can scale other values or Activate Digital Outputs with GRT or LSS

Start to configure the block "SCP", first go to I1- INPUT and open, change Binary to DECIMAL; we can see in the window Inputs from the AI Module that we have added above

Now and Very Important add the Analog Input I:1.0 to the block SCP

Then select the N7 INTEGER Block in the side and add it to the OUTPUT of the block "SCP"; it means that Instruction has the first scaled Final Value in Real Time; with this variable N7.0 we can create more instrucctions and new scaled values, the block with the first scaled is OK

Now go to scale 2 blocks SCP

For the First Block

• Scale the INT value from Analog Input I1.0 in 4-20mA VS 3277-16384; and then Scale Software value in 400-2000 ONLY for understand 4-20mA (in a PLC you can create a lot of instrucctions, always is better create a good programmation that helps to monitoring, scaling and best understand of the program


• OUTPUT of the value N7:0 is the value between 400 y 2000; very similar to 4 and 20mA, remember all Analog Scaled work as Linear Functions

For the Second Block

• Scale by the configuration the Values MIN and MAX from the Instruction N7:0 (400-2000); now have a new result value N7:1 (0-100) and this new instructions we will use to Activate Outputs


• OUTPUT the value N7:1 is the final scaled value 0-100; TAKE NOTE, the final value is the recommended by the Sensor Manufacturer; Sensor that works with 4-20mA have a Range measurement 0-100, this is not a false value, in the image below you can watch a Humidity Sensor 2-wire with Output 4-20mA

Finally to create digital outputs in relation to the measurement we can use instructions "Higher or Lower value to Output" add the blocks GREATHER THAN or LESS THAN

Next image example show the values of an Analog Input that shows how the value is scaled and what parameters change, when the "Greater Than" is higher that the value assigned by us, the Output GRT is activated