How to Save New Calibration Constants on NI SLSC FIU Cards

Updated Mar 2, 2023

Environment

Hardware

  • SLSC-12252
  • SLSC-12251

Driver

  • NI-SLSC

This article descibed the steps to change the values for Gain and Offset of the current transducer on the NI-SLSC FIU cards 12251 and 12252.
The article uses the LabVIEW API of NI-SLSC.

Preperation:
Follow steps 1 to 7 of Calibration section for SLSC-122x Feature Usage Document.

Steps to update the values:
  1. Use the LabVIEW example Backup NVMEM to File.vi and select the capabilites section of your SLSC card in the NVMEM area selection. Run the VI.
  2. Create a copy of the created bin or json file, so you have a backup, which you can use to return to the original state.
  3. Open the file with a text edidor, and search for the relevant entries NI.FIU.CurrentTransducer.Offset and NI.FIU.CurrentTransducer.Gain. The files always contain mutliple entries, one for each current transducer (16 on SLSC-12251, 8 on SLSC-12252). Change the values to the new values, which you calculated during the preperation, and save the modified file.
  4. Use the LabVIEW example Restore NVMEM from File.vi:
    • Open the block diagram, and scroll to the Set NVMEM Bytes.vi.
    • Connect a string control to the seriel number input.
    • Connect a string constant to the password input, and enter ni as constant.
    • Go to the front panel, enter the serial number, select the modified backup file, and select the capabilites section of your SLSC card in the NVMEM area selection. Run the VI.

After a restart of the SLSC chassis, you will see, that the values for NI.FIU.CurrentTransducer.Offset and NI.FIU.CurrentTransducer.Gain have the new values.

Next Steps

Verify, that the new calibration works by some test measurements with known currents.