During normal operation the alarm light will illuminate and the TTL output (pin # 2) will go high (+5V) if the pressure becomes less than the set point.
To view the setpoint using the serial connection, send “L<CR>”.
The set points can be adjusted using either the controls on the gauge or the serial connection. To adjust a setpoint using the manual controls, place the HPM-2002-OBE in either setpoint mode (High or Low). Next, use the ADJUST rotary encoder until the desired setpoint is displayed. Finally, place the HPM-2002-OBE back in the Run mode. The new set points are now stored in the HPM-2002-OBE’s memory. Or simply use one of the Modify High Setpoint Commands e.g. “H={m.dd}E{=+e}<CR>”.
3.3.12.Run Mode
The HPM-2002-OBE will automatically enter the Run mode upon start-up. This is the mode for normal operation and the mode in which the instrument will spend most of its time. In the Run mode the HPM-2002- OBE will continuously monitor the pressure; update the alarm conditions, and update the display about ten times a second.
3.3.13.Cal Mode
Optimal performance of the HPM-2002-OBE is achieved by performing in situ adjustments to the calibration coefficients in the Cal mode. There are three calibration coefficients. These are the zero coefficients, the midrange coefficient, and the atmosphere coefficient. Once a tube has been fully calibrated the midrange coefficient should never need further adjustment, but it may be helpful to adjust the zero coefficient or the atmosphere coefficient under certain circumstances. The CAL MODE presupposes that the operator is applying a known pressure of the correct gas composition (see GAS MODE). The factory calibration points are 800 Torr, 7 Torr, and < 10-6Torr. The user’s calibration points are not required to be exactly those values, but should be somewhat close, and must be within the ranges shown in the figure on page 15. The HPM-2002- OBE detects the voltage signal within the sensor tube, which is converted and displayed as a pressure reading. The resulting pressure reading determines which of the three coefficients will be adjusted.
HPM-2002-OBEVacuum Gauge | Page 22 of 39 |