Yutaka,

See Answers below.

At 09:48 AM 4/27/98 -0500, you wrote:
>Hello Rod-san,
>
>I have couple question about calibration and tuning at 469D.
>1, Y3 actuator cables cut out about 1.5m, do I need recalibration? (
>especially Y3  LVDT zero was moved about 30mm)

	If the original cable is only that much shorter, I do not think that
	you would have to re-calibrate.  I am surprised that the zero shifted
	by that much though.  A good way to check is to run Y3 end-cap to end-
	cap and compare the read-outs w/ the other horizontal actuators.  They
	were all within about 1-2 mm of each other before.  If more than 3-4 mm
	difference, then you should re-calibrate.

>2, If I have to do, would you please right procedure to use uniaxial
>controller?

	Uniaxial Controller:
	1. With hydraulics OFF, select Uni-axial controller from Service Menu.
	2. Select actuator to control (Y3).
	3. Make sure gain is 0.5 to 1.0, the gain can easily be 1.0 for NTT.
	4. Make sure DC error = 0 by adjusting setpoint to get uniaxial output
		to equal zero.  Uniaxial Output can be put on a meter or the
		oscilloscope to verify.  Adjust setpoint to get it to zero.
	5. Turn on hydraulics and lower the parking frame.
	6. Can move table still, but Y3 will stay put, unless it is unhooked
		from the table.  But the table can be moved in DOF control out
		of the way if you want more room.
	7. Important step is #4.  If error NOT zero, get big bump.  Brad is not
		here right now so I will check w/ him tomorrow if there's
		anything else.

>3, About horizontal actuator, all plus displacement feedback means
>actuator extend, am I collect?

	YES, you are correct.  Longitudinal + command will extend X1
	and retract X4 by inverting command to X4.  All MTS seismic systems
	use the convention of Plus=Extend on ALL actuators.  The 469D will
	invert the commands as necessary for degree-of-freedom control.

>
>I really screw up my mind, Please help me!!

Nah, only Yumi can do that!!
Rod Larson
