DH Instruments PPCH-G, Руководство по эксплуатации и обслуживанию

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3. OPERATION
Page 75 © 2007 DH Instruments, a Fluke Company
The PPCH-G RS232 test can fail for three reasons:
1. The RS232 cable being used is incorrect (see Section 4.2.1.1 for
information on the correct cable).
2. COM1 and COM2 do NOT have the same serial communications settings
and therefore cannot communicate together (see Section 3.5.2.1 to set
the COM ports).
3. COM1 or COM2 is defective.
The reason for failed communications is almost always a cable or incorrect RS232
interface settings. Be sure that these are correct before concluding that a COM
port is defective.
3.5.3 <3HEAD>
 PURPOSE
To view or change the properties of the HEAD function (see Section 3.3.7) including the unit
of measure of length for head height entry and the test fluid type and species for density
calculations.
 OPERATION
From the MAIN RUN screen, pressure
[SPECIAL]
,
<3Head>
.
Select the desired height unit of measure and press
[ENT]
.
Select
<1gas>
or
<2liqud>
depending on the pressurized medium between the PPCH-G and
the height at which pressure is to be calculated. Select the gas or liquid species. The liquid
selection
<3User>
, is to create a custom liquid with a user entered density.
Use
[HEAD]
to set a fluid head height if desired (see Section 3.3.7).
3.5.4 <4RESET>
 PURPOSE
To reset various PPCH-G settings to default or factory values.
 PRINCIPLE
PPCH-G stores its user definable settings in non-volatile memory. The reset menu allows
the user to selectively or completely reset these settings to factory defaults. This clears out
any settings that the user has made, and should be used only to restore the PPCH-G to a
known state. PPCH-G goes through its power up sequence after any type of reset is
executed.
PPCH-G reset functions will change current settings to factory defaults. These may
include settings vital to PPCH-G operation and affecting the calibration of the quartz reference
pressure transducers (Q-RPTs). Reset functions should only be used by qualified personnel with
knowledge of reset consequences. Reset functions should not be used experimentally.