How to convert a 16-bit variable to 64-bit

Hello everyone, I am reading registers from a Siemens PAC2200 64 bit, how do I display this value correctly by node red? I need to join the 4-number vector to just one string.
Thank you very much im1 im2

You could look into type typed arrays or the node.js buffer as it has functions like readDoubleLE() and readDoubleBE().

Here is a quick mock up using JS Typed Arrays (its a bit of a cludge but might be enough to nudge you in the right direction..

NOTE: you may have to swap your integers as I dont know endiannes of your data or how its stored in PLC or how the driver your're using handles the data bytes...