How to activate the temperature interpolation (staircase pattern) (beta)

This article shows you how to activate the temperature interpolation to smooth the staircase patterned curve.

If you haven't been invited to participate in the beta program for this integration, but you are interested in participating and testing the feature, please sign up here.

Beta means that the features are being tested with a select group of users to help us identify minor flaws under everyday conditions that we cannot reproduce internally. Therefore, it will be necessary that you share feedback with us and let us know whenever you come across some unexpected behavior.

Why does Cropster show a staircase pattern?

There are two scenarios that cause a staircase patterned curve in the Roasting Intelligence  (RI): 

  • The updating interval of the roast machine's PID and the RI are not matching
  • The PID provides the RI with integer temperature values only

Mismatching intervals

The Roasting Intelligence (RI) requests and updates the temperature values from the roast machine's PID once every second. When the interval of the roaster's PID is higher than 1 second, the values sent to the RI are inconsistent which results in a shaky (staircase-patterned like) curve. 

Integer temperature values

When the roaster's PID only supports integer temperature values. The temperature does not change 1°C/F each second (especially after turning point). Therefore the RI receives and prints the same value over a couple of seconds before the temperature rises 1° C/F which results in a staircase pattern.

Interpolation of temperature readings

To smooth the temperature curve, we have developed a filter to smooth temperature curves. 

Which connectors support the temperature interpolation?

The filter can be enabled/disabled for the following connectors: 

  • Generic Modbus over Network TCP/UDP (if storage format integer is selected)
  • Generic S7 over Network (if storage format integer is selected)
  • Generic Modbus over serial port (if storage format integer is selected)
  • Besca Auto PLC
  • Diedrich PLC
  • Mill City PIDs (MCR Series only)
  • Petroncini PLC

The connectors below come with an integrated interpolation filter (that is enabled by default and can not be disabled): 

  • Arc Roaster
  • HB Roaster
  • CoffeeTech Beta (PID over serial port) - Ghibli model
  • IMF with Legacy PLC
  • Ozturk PLC
  • Trinitas - T2

How to enable the filter?

To enable the interpolation of temperature readings, please follow the steps outlined below:

The following applies, after the roast machine has already been successfully connected to the computer, according to the setup and installation manual for your roast machine. 

  1. Download the Roasting Intelligence (RI) beta app from
  2. The Cropster installer leads you through all the installation steps.
  3. Open the RI by double-clicking the Cropster Beta icon on the desktop and log in.
  4. Go to Account > Preferences > Machine tab. 
  5. If you are using one of the connectors mentioned above, you will find the Filter option upon opening the Preferences. Check the box next to Allow interpolation of temperature readings to enable the temperature interpolation. 
  6. Save the changes and restart the RI. 

Screenshot 2021-06-28 at 14.13.40-1

Note: If you are experiencing this issue with staircase-patterned roast curves, and the filter is not available for the connector you use, please reach out to and share the following information:

  • A roast ID-tag and picture displaying the staircase pattern
  • Roast machine manufacturer, model, and manufacturing year
  • Your RI log files