DH Instruments PPC2+, Manual

Page: 164 / 166

PPC2+™ Operation and Maintenance Manual
©2001 DH Instruments, Inc.
Page 156
Head A difference in height between the PPC2+ reference level and the DUT.
Hold Limit An automated pressure control parameter. Maximum acceptable difference
between the current pressure and the target pressure value.
Measurement Mode Whether pressure is being measured relative to absolute zero or vacuum (absolute
mode) or relative to atmospheric pressure (gauge mode).
PA Pressure adder, used to offset an RPT range or barometer in calibration.
PM Pressure multiplier, used to adjust span of an RPT range or barometer in
calibration.
Rate The rate of change of the current pressure. Indicated in the main run screen when
control is suspended.
Ready (<*>)/Not Ready
(<
↑
> or <
↓
>)
Indication used in automated control to indicate when control is complete and data
may be taken within control parameters.
RPM Reference pressure monitor manufactured by DHI. Models are RPM1, RPM2,
RPM3.
RPT (Reference
Pressure Transducer) 1. The transducer used by PPC2+ for high accuracy pressure measurement. The
RPT in a single RPT PPC2+ or the higher pressure range RPT in a dual RPT
PPC2+ is referred to as the Hi or primary RPT. 2. The lower pressure range RPT
in a dual RPT PPC2+ is referred to as the Lo RPT. RPTs are designated by a
leading A or G (absolute or gauge) followed by four numbers indicating the
maximum range of the RPT in psi (e.g., A0100).
SPLT
Self Purging Liquid Trap. An optional device to protect PPC2+ from liquid and
particulate contamination returned from a DUT.
Stability Limit A limit expressed in units of pressure per second (e.g., psi/second). The stability
limit is used as the Ready (<*>)/Not Ready (<
↑
> or <
↓
>) criterion. Ready (<*>) if
inside stability limit. Not Ready (<
↑
> or <
↓
>) if stability limit is exceeded.
Static Control Control mode in which the pressure is set near the target value and then shut OFF
and allowed to evolve freely.
Target The value to which automated pressure control attempts to set and maintain the
pressure.
UL
Same as Upper Limit.
Upper Limit A range specific maximum value of pressure not be exceeded and at which PPC2+
will abort pressure setting and buzz.
User Level Levels of security that can be set to protect certain PPC2+ functions from being
accessed.