MKS UniMag 971, Руководство по эксплуатации и установке, Страница: 20 / 44

971 UniMag ™ Operation manual 17
Cold Cathode protect setpoint
The Cold Cathode protect setpoint automatically turns off the Cold Cathode high voltage if the cold cathode
measurement exceeds 5.00E-3 Torr for 120 seconds. The protect setpoint can be turned off (disabled) or
time set between 0 and 999 seconds.
Command: @253PRO!ON;FF
Command values: ON (120), OFF, 0 to 999 seconds
Command reply: @253ACK120;FF
Query: @253PRO?;FF
Query reply: @253ACK120;FF
Factory default: OFF
If FP is set to “ALWAYSON” the protect setpoint is automatically disabled. (See page 15)
The 971 is factory calibrated when delivered and in many applications further calibration is not required.
If the sensor element has been contaminated or damaged by process gases, adjustment of zero and full
scale can be executed to compensate for small measurement errors.
Pressure unit calibration
The transducer can provide digital and analog output in torr, mbar and Pascal pressure units.
When changing pressure unit all parameters such as setpoint settings are automatically converted to the
new unit, so it will represent the same pressure level. All pressure parameters such as setpoint settings and
calibration values must be entered in the actual transducer unit setting.
Change of pressure unit calibration setup:
Command: @253U!PASCAL;FF
Command values: TORR, MBAR, PASCAL
Command reply: @253ACKPASCAL;FF
Query: @253U?;FF
Query reply: @253ACKTORR;FF
Factory default: TORR
The torr unit is most common in the US and mbar is most common in Europe. Pascal is the official pressure
unit as specified by SI (from the French
Le S ystème I nternational d'Unités ) and is widely used in Asia.