Hey @janek,
I'm going to continue here, to keep the other discussion focussed on the UI-node.
Do I understand this correctly? Your ML9060 sensor is connected via I2C to the RPI pins of your Raspberry, and then you use a third-party application (which you trigger via the Exec-node) to read data from the RPI pins into your Node-RED flow.
I have no experience with the I2C yet, but have you already tried for example the node-red-contrib-i2c node. It might (??) be faster to read the I2C data directly from Node-RED? I'm pretty sure that other people on this forum might be able to help you with this ...