PG7000™ OPERATION AND MAINTENANCE MANUAL
© 1998-2008 DH Instruments, a Fluke Company
Page 170
The program should then instruct the user to open the bypass valve, crossfloat the
pistons to within about 150 mg, close the bypass valve, set both pistons to about
+1.0 mm, open the bypass and press ENTER. The piston positions along with the real
time crossfloat fall rate difference (the difference between the current fall rate difference
and the natural fall rate difference) should be displayed and updated until the user elects
to start the crossfloat by pressing ENTER:
Send:
“HLDPPOS”
(Request the reference and tare PG piston positions)
Reply: “-0.4, -0.5, 10.2” (Reference and tare piston positions, real time crossfloat fall
rate difference)
When ENTER is pressed, start the crossfloat measurement function. Send:
Send:
“HLDLINEP=NEXT”
(Request the crossfloat function to start)
Reply: “BUSY2” (Indicates that the crossfloat function is running)
The status of the crossfloat step can be monitored by sending the HLDLINEP command
until the reply is no longer “BUSY2”. The reference, tare piston positions and the
crossfloat fall rate should also be monitored:
Send:
“HLDPPOS”
(Request the reference and tare piston positions)
Reply: “0.4, 0.5, 6.9” (Reference and tare positions, average crossfloat fall rate
difference since the start of this function)
Send:
“HLDLINEP”
(Check if the step is completed)
Reply:
“
BUSY2
”
(Step is still busy, continue in this loop)
Reply:
“
OK
”
(Step is still complete; go to next step)
The results of the crossfloat fall rate measurement step can now be obtained:
Send:
“HLDXFLT”
(Request the crossfloat results)
Reply: “6.9.1, 0.046 g” (Crossfloat fall rate difference and recommended trim mass
adjustment)
Reply:
“
ERR #41” (One of the piston positions has exceeded
±
2.9 mm)
The crossfloat fall rate measurement function can be repeated if the user is not satisfied
with the step, or if one of the piston positions has exceeded
±
2.9 mm, by returning to
Step (9).
Send:
“HLDLINEP=REPEAT”
(Request the crossfloat function to start again)
Reply: “OK”
And then:
Send:
“HLDLINEP=NEXT”
(Request the crossfloat function to start again)
Reply: “BUSY2”
The crossfloat fall rate measurement results can be saved:
Send:
“HLDLINEP=NEXT”
(Request to save the crossfloat data)
Reply: “OK”
Reply: “ERR #40” (Current step not complete or failed)
You are now in high line differential mode. High line differential target pressures can be
accomplished using the normal PG7000 remote commands “PS” and “MS”, or locally.
The natural fall rate difference and crossfloat piston-cylinder temperatures for the last line
pressure setting sequence (same is the
<2view>
screens of HL dif mode) can be
reviewed anytime using the “HLDVIEW” command.
