DH Instruments ADCS-601 - Piston Position Detection Adjustment

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ADCS-601™ OPERATION AND MAINTENANCE MANUAL

6.7 PG7601, PISTON POSITION DETECTION ADJUSTMENT

The PG7601 piston position detection system is used to determine the position of the PG7601’s piston within

its stroke. If the piston position detection system is out of adjustment, the piston may not be floating freely

when expected. This will cause erratic pressure control and unstable and incorrect pressure at the set point.

Refer to piston stroke schematic Figure 57.

To automatically adjust the PG7601 piston position indication system, proceed as follows:

Prepare the ADCS-601 system for local operation of individual components:

Vent the ADCS-601 system by pressing the [VENT] button on the ADCS Run Screen. Wait for the

operation to complete.

Disconnect any device that is connected to the TEST(+) port at the port and plug the port using the

plug provided.

Press the [Pause] button on the ADCS Main Tool Bar to suspend remote communication within the

ADCS-601 system.

Press the [ESC] key on the PG7000 Terminal and on the PG7601’s PPC3 Pressure Controller

(PPC3-700K) to allow local control.

Load all the binary masses on the PG7601: On the PG7800 Terminal, press [SPECIAL], <8AMH>,

<2control>, <2discreet>. Use the arrow keys to move the cursor and select all the binary masses.

Press [./SETUP] next to each value (<1>, <2>, <4>…<64>) so that there is a <*> next to each value.

Enter <0> for <Main:>. Then press [ENT] to cause all the binary masses to load.

Run the PG7601 piston position calibration function:

Press [ESC] on the PG7000 Terminal until operation returns to the main run screen.

Press [SPECIAL], <7cal>, <5Pposition>, <2cal>.

When the prompt <Hold piston at max down stop> appears, press [ENT]. The piston is already at

the down stop because the pressure under the piston is vented and 7.2 kg of mass is loaded.

When the prompt <Hold piston at max up stop> appears, go to the PG7601’s PPC3 pressure

controller (PPC3-700K) and set a pressure of 200 kPa. Press [ENT] on the PPC3 front panel, enter

200 kPa (or equivalent in current pressure unit of measure) and press [ENT]. Observe the PPC3

display until the pressure reaches approximately 200 kPa. Press [ESC]. The pressure may then

drop a bit but should hold above 175 kPa. Go back to the PG7000 Terminal and press [ENT]. When

<Save new cal> appears, select <2yes>.

If desired, check the calibration. Select [SPECIAL], <7cal>, <5Pposition>, <1view>. View the

position of the piston. When the piston is at the upper stop (pressure of 200 kPa with current mass

load) piston position indication should be +4.5 mm. When the piston is at the bottom stop (pressure

vented with current mass load) piston position indication should be –4.5 mm. If this is not the case,

repeat the calibration process.

Resume normal ADCS-601 operation:

Press [ESC] on the PG7601 until its main run screen appears.

Press [VENT] on the PPC3 and wait for vent to complete.

Press [PAUSE] on the ADCS Main Tool Bar to resume normal ADCS-601 system operation.