pressure-logger

Reads, displays, and logs the pressure measured by two VG (now EpiMAX) PVCi ion gauge controllers of an Omicron LT STM/AFM microscope. Communication with the controllers uses MODBUS over RS232, the logfiles are in HDF5 format.

Needs:

• NI Modbus Library
  https://forums.ni.com/t5/NI-Labs-Toolkits/LabVIEW-Modbus-API/ta-p/3524019
  tested with version 1.1.5.39

• h5labview HDF5 bindings for LabVIEW
  http://h5labview.sf.net/
  tested with version 2.13.4.143

• HDF5 library
  https://www.hdfgroup.org
  tested with version 1.8.19

Writes:

• yyyy-mm-pressure-log.h5, a monthly logfile in HDF5 format;
• pressure-logger-output.log, a text file with errors and start/stop times.

It is reboot-tolerant, performing a clean quit if LabVIEW exits.

Usage

Before running main-pressure-logger.vi, edit its source code to set:

• serial port parameters;
• MODBUS unit IDs of the PVCi controllers;
• path to the folder containing the logfiles.

main-autorun.vi opens and runs main-pressure-logger.vi. It can be added to the Windows startup folder to run the program at startup.

main-log-viewer.vi is as simple viewer for the recorded logs.

Typical errors

In our setup we sporadically get the following error codes:

• 538172
  frequency: 2.3 errors/hour or 1 error every 7.8k MODBUS reads;
  description: MODBUS function data mismatch, the response doesn't match the request;
  See here.

• 538170
  frequency: 1.6 errors/day or 1 error every 270k MODBUS reads;
  description: MODBUS function code mismatch, the returned function code does not match the requested data.

• 56
  frequency: 0.5 errors/day or 1 error every 860k MODBUS reads;
  description: time out or CRC error.