PPCH™ OPERATION AND MAINTENANCE MANUAL
© 2009 DH Instruments, a Fluke Company
Page 126
UL
Purpose
Read or set an upper limit for the current range.
Command
Query
“UL
n
”
“UL?”
Classic “UL=
n
”
“UL”
Arguments
n:
The upper limit pressure in the current pressure unit and measurement mode.
Remarks
The PPCH has an upper limit for each range and for each measurement mode (gauge and absolute).
New automated pressure control targets cannot be greater than this value. If the pressure
does exceed the upper limit, the pressure display flashes, and pressure control stops.
Manual increases in pressure are not allowed as long as the pressure is above the upper
limit. Decreases in pressure are allowed. This feature should always be used to prevent
accidental over pressure of a device under test.
Example
(enhanced)
Cmd sent:
Reply:
“UL 10”
“10.000 MPa a” (No reply if GPIB-488)
Example
(enhanced)
Cmd sent:
Reply:
“UL? 10”
“10.000 MPa a”
Example
(classic)
Sent:
Reply:
“UL=1000”
“10.000 MPa a”
Errors
ERR# 6:
The argument is out of range.
See Also
3.4.4
UNIT
Purpose
Read or set the pressure unit of measure unit and measurement mode.
Command
Query
“UNIT
unit (, ref
”)”
“UNIT
unit
g
(, ref
”)”
“UNIT
unit
a
(, ref
”)”
“UNIT?”
Classic “UNIT=
unit (, ref
”)”
“UNIT=
unit
g
(, ref
”)”
“UNIT=
unit
a
(, ref
”)”
“UNIT”
Arguments
unit:
ref:
The text corresponding to the pressure unit of measure.
The optional unit reference temperature only if the unit is “InWa”.
Remarks
This program message determines what unit of measure and may determine what
measurement mode is used to display pressure values. Refer to Table 16 for a detailed list of
the units available and their labels.
The unit text must be followed by ‘a’ if absolute measurement mode is desired, or ‘g’ to specify
gauge measurement mode. There can be a space between the unit text and the ‘a’ or the ‘g’.
If neither ‘a’ nor ‘g’ is specified, the unit will change but the measurement mode will remain
the same.
If the unit specified is “InWa”, an optional second argument “
ref”
can be set. The “ref” can be
4, 20, or 60 corresponding to InWa at 4 °C, 20 °C or 60 °F. If this second argument is not
given when the unit is “InWa”, then the reference temperature is assumed to be 20 °C. he fifth
character of the reply is always ‘a’ for absolute mode, or ‘g’ for gauge mode. White spaces will
proceed this character if needed. The temperature reference is added to the reply only if the
unit is “InWa”.
Example
(enhanced)
Cmd sent:
Reply:
Sent:
Reply:
“UNIT kPaa”
“kPaa”
“UNIT InWag, 4”
“inWag, 4”
Example
(classic)
Sent:
Reply:
Sent:
Reply:
“UNIT=kPaa”
“kPa a”
“UNIT=InWag, 4”
“inWag, 4”
Errors ERR#
7:
ERR# 6:
The
unit
is invalid.
The
ref
is invalid.
See Also
“MMODE”, “MODE”
3.3.2, 3.3.3
