All ranges of Laureate analog signal conditioner boards and analog output boards are factory calibrated, with calibration factors stored in EEPROM on these boards. This allows different ranges to be selected via plug-in jumpers and different boards to be plugged into the mete, with no need to recalibrate the meter as a system. Calibration by Laurel uses CalWincustom software working with programmable Fluke 5500A calibrators. These are calibrated by Fluke annually and are self-calibrated weekly. The list of the equipment used to calibrate a specific Laureate meter or counter and the calibration dates of this equipment are available as an option by ordering aCertificate of Calibration.
Annual calibration of Laureate analog signal conditioner boards can be performed by a customer’s cal lab using an external standard, a PC, and Laurel’s Instrument Setup (IS) Software, which can be downloaded at no charge. For communications, the meter must be equipped with an RS232 board or USB board, and an appropriate PC communication cable. Following calibration, the communication board can be removed and be used to calibrate another Laureate meter. Laureate transmitters come standard with RS232/485 or Ethernet communications, as ordered.
To use IS Software with a signal conditioner board, establish communications with the Laureate meter or transmitter. From the Main Menu:
To calibrate, first select the Zero range, set jumpers to the signal conditioner board as shown for 0 Vdc, apply a short circuit to the input, and press Ready. Then select the other ranges to be calibrated, set jumpers for each range, apply the known full range signal, and press Ready. Press End to exit the calibration procedure when you have completed all ranges. IS Software will display “Calibration Complete”. Verify the jumper settings by referring to the latest meter or transmitter user manual.
After exciting the calibration procedure, reset jumpers and use IS Software to return your meter to the desired working setup. From the Main Menu, press File => Open Setup to retrieve your previously saved setup file, then press DPM => Put Setup to download that setup file back into your meter. Note that calibration data is not part of the setup file but is entered separately by the calibration procedure.
For frequency and rate measurements with the dual-channel signal conditioner board, or for rate measurements with the quadrature signal conditioner board, calibration is limited to making a correction in parts per million (PPM) to the quartz crystal oscillator on the microcomputer board. This correction is stored in EEPROM in the microcomputer board, so that signal conditioner boards can be changed with no need to recalibrate the counter.
For time base calibration, counter calibration may be performed in the field using the front panel push buttons:
To verify calibration of the analog output board, select the Scale, Offset scaling method, set Scale to +00000, and set Offset to a desired number. The counter or transmitter reading will then be the same as Offset. Set Offset to +00000 for the Lo Range Reading and to +10000 for the Hi Range Reading. Use an external calibrated meter to verify that the desired analog outputs are achieved. The meter should have at least 5-digit accuracy, since the resolution of the analog output is 16 bits, or 0.0015% of full scale.
To calibrate the analog output board so that its full scale ranges are truly 0-20 mA, 0-10V, 4-20 mA or -10V to +10V, use Laurel’s CalWin30 calibration software in Manual mode.