9001-0004 - hyd test fixture - technical reference manual · assembly cooling shroud ... this time...

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Technical Reference Manual

Document# 9001-0004

Hydraulic Test Fixture

Project: 102K15

Released: November 3, 2005

Revised: February 22, 2006 Added production test procedure

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Project# 102K15

Document# 9001-0004

Revised: 2/22/2006

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Notice: This report is proprietary to Air Tractor. It is provided to our customer with the understanding that each recipient agrees to disclose any information contained within it to only those persons in its organization having a “need to know”.

Table Of Contents

Production Test Procedure ...........................................................................................3 Connections required for an FRDS system...................................................................3

Production Test Sequence / Parameters........................................................................4

Production Operator Test Instructions..........................................................................4

System Overview ...........................................................................................................6 Operation Overview ....................................................................................................6

Hardware Overview.....................................................................................................7

Connections...............................................................................................................10

Temperature Control & Sensors ................................................................................11 Temperature Control .................................................................................................11

Temperature Error .....................................................................................................11

Manual Valve On / Run Pump-Start Switch..............................................................12

Hydraulic Valve ........................................................................................................12

Run Pump-Start Switch .............................................................................................12

Pressure Sensor ...........................................................................................................12

Run Mode Switch ........................................................................................................13

Cycle Descriptions .......................................................................................................14

Power / Cycle In Progress Light .................................................................................14

Input / Output Usage...................................................................................................15


Project# 102K15

Document# 9001-0004

Revised: 2/22/2006

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Production Test Procedure The test fixture controller has been designed so that it can be used with an existing FRDS

unit (production test stand) or as part of a stand alone system shown later. The following

sections outline the operation of the system as well as the operator actions required.

Please read the remainder of this document to fully understand the test fixture’s design

intent and capabilities.

Note that a custom reservoir has been built that includes temperature sensors and a heater

element to control the temperature of the oil. This reservoir must be used in conjunction

with the test fixture controller for the oil temperature to be controlled and monitored.

Figure 1 ~ Pump test fixture controller front panel

Connections required for an FRDS system

1. Assembly cooling shroud and cooling blower to pump shroud assembly

2. Make the following electrical connections


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3. Connect the hydraulic pressure sensor to the fixture controller (the standard FRDS

pressure sensor will plug into the test fixture)

4. Connect the one wire from the text fixture to the hydraulic pump relay

5. Connect one wire from the test fixture controller to the bleed solenoid

6. Connect the (+) Battery and (-) Battery to the test fixture controller

Note that the same test can be run without using an FRDS system with no changes to the

test fixture controller. The setup is shown using one external valve, an accumulator, a

flow control valve, and a pump. This setup is shown in Figure 2 ~ Test Fixture setup

Production Test Sequence / Parameters

The recommended sequence of events for testing the pump is as follows:

1. Preheat the reservoir oil to 175° F

2. Turn on the pump cooling blower

3. Turn on the pump to pressurize the hydraulic accumulator to 3000 PSI

4. Wait until the pump reaches 3000 PSI and turns off the pump.

5. Discharge the accumulator to 0 PSI

6. Waits 60 seconds

7. Starts at step 1 & repeats 4 times

8. Once 4 pressurization cycles completed in step 6, waits for 5 minutes

9. Starts at step 1 again

10. Repeat the process above for 1 hour, then measure the time required to fill and

accumulator. The test fixture automatically does this.

Production Operator Test Instructions

1. Make the connections to the pump relay, bleed solenoid valve and pressure sensor

on the production FRDS test stand.

2. Pull the ESTOP on the test fixture controller out.

3. Turn the HEATER switch to the “ON” position. The heaters will start heating the

oil in the reservoir to 175° F. This temperature is automatically controlled by the

fixture.

4. Turn on the pump cooling blower.

5. Set the MODE switch on the front panel to 0 PSI – TMR.

6. Press the “START” button on the panel.

7. The text fixture will run a short warm up cycle to get air out of the system then

automatically run the recommended production test sequence.

8. Let the fixture run for 60 minutes.

9. Observe the fixture and write the time required for the pump to pressurize the

accumulator to 3000PSI. This time is displayed on the counter module each time

the pump run.

10. Verify that the battery voltage is at least +24 Volts

11. Record the time to pump up four times.


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12. If the longest time to pressurize is greater than 45 seconds, the pump is bad.

Check battery voltage and verify that the pump cooling blower is operating

correctly. Retest the pump if necessary.

13. Stop the test fixture by turning the MODE switch to the “OFF” position.

Depressing the ESTOP button will also remove power from the entire system.

Note: If the pump fails to pressurize the system to 3000PSI within one minute during the

test sequence, the fixture will automatically shut down and the POWER/IN CYCLE lamp

will go off & flash once every 5 seconds. The pump should be retested with an operator

present if this happens. In general this indicates that the pump is bad, cooling is

insufficient or the battery is low.


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System Overview

A test fixture has been developed to test & qualify production hydraulic pumps before

shipment on an FRDS system. The goals of the fixture are as follows:

� Control oil reservoir temperature to within 10 degrees F.

� Test the pumps performance at elevated temperature before shipment.

� Perform cycle testing on pumps if desired.

� Provide the operator with the time required to pressurize a hydraulic accumulator

to 3000 PSI (if in one of the Timer modes).

� Provide the operator with the total number of charge/discharge cycles made by the

pump (if in on of the counter modes).

While the test fixture does not measure actual pump flow, it effectively provides a

qualitative measure of the pumps performance. The time required to charge a hydraulic

accumulator is used to determine if the pump is operating satisfactorily. Time to

pressurize the accumulator is directly correlated to the pumps flow characteristics across

the entire pressure range we are interested in so this is a valid test method.

Operation Overview

The test fixture performs the basic functions outlined below:

� Controls the oil temperature to within +5 degrees F

� Displays time & count information to the operator

� Controls a pump and valve to achieve the following sequence of events

1. Turns on the pump to pressurize the hydraulic accumulator to 3000 PSI

2. Turns off the pump when the pressure reaches 3000 PSI

3. Discharges the accumulator to either 0 PSI or 2200 PSI depending on mode

selected

4. Waits for a specified amount of time (60 seconds)

5. Starts at step 1 & repeats 4 times

6. Once 4 pressurization cycles completed, waits for 5 minutes

7. Starts at step 1 again

The sequence of events for the test fixture is shown in the following sections. Note that

the temperature controls and valve on/run pump switch can be viewed as independent

processes.


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Hardware Overview

The test fixture is comprised of the basic components outlined below:

� Programmable Logic Controller – Used to sequence the test

� Counter Module – Used to display pressurization time or cycle count to operator

� Amp meter – Used to display the amperage consumption or voltage to the pump

motor

� Switches & Light – Used to allow the operator to control fixture actions

� Hydraulic Reservoir – Oil for system testing is stored

� Heating Element – Heating element embedded into reservoir to heat the oil up to

the specified temperature

� Variac – Used to limit the maximum amount of energy that is available to drive

the heating element. This is not required but was used to avoid local boiling of oil

around the heating element. Set this to 80%.

� Temperature Gage – Embedded into the hydraulic reservoir to display the oil

temperature to an operator.

� Setpoint Temperature Sensor – Sensor embedded into the hydraulic reservoir that

switches once the desired oil temperature has been reached. The PLC monitors

this sensor and controls the heater based on this sensors state (on or off)

� Alarm Temperature Sensor - Sensor embedded into the hydraulic reservoir that

switches once the maximum allowable oil temperature has been reached. The

PLC monitors this sensor and can shut the test down and the heater off based on

this sensors state (on or off).

� Hydraulic Relay – Used to turn the pump on and off.

� Hydraulic Pump – Used to pressurize the system and is the device under test

(DUT).

� High Pressure filter – Filter used to remove oil contaminants.

� Hydraulic accumulator – One gallon accumulator that is pressurized by the pump

during the test. The pre-charge on this accumulator must be set to 1650 PSI for

test results to be valid.

� Pressure Sensor – Used to measure system hydraulic pressure. The PLC uses this

sensors input to control the pump.

� Hydraulic Valve – Used to dump pressure from the accumulator back to the

reservoir once the pump has pressurized the accumulator.

� Flow Control Valve – Used to limit the oil flow from the hydraulic valve when

dumping accumulator pressure back to the tank.

The test fixture is shown in the figures below:


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Figure 2 ~ Test Fixture setup


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Figure 3 ~ Operator panel for test fixture


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Figure 4 ~ Electrical enclosure used to control test fixture

Connections

The following connections are required:

� External +24Vdc~28Vdc from battery to power valves and relays.

� External 120VAC input to power the PLC and heater

� External pressure sensor connector

� External Setpoint temperature sensor (built into hydraulic reservoir)

� External Alarm temperature sensor (built into hydraulic reservoir)

� Bleed solenoid valve on pump

� Hydraulic valve (optional)

� Heater element (built into hydraulic reservoir)


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Temperature Control & Sensors

Temperature Control

A temperature sensor is used to sense when the oil has reached the preset temperature.

The sensor has normally open contacts that will open once the oil has reached the preset

temperature. This sensor is connected to input X10 and will open (input to PLC will go

off) when the set point temperature is exceeded.

The temperature sensor connected to input X10 is used to control the temperature of the

oil. The heater element is controlled by output Y7.

PLC POINT

X10 Temperature Setpoint Sensor

X11 Over Temp Fault Sensor

Y7 Heater AC Output

Y3 Buzzer

If X10 = High for more than 10 seconds, turn on output Y7 (heater on)

If X10 = Off, turn off output Y7 (heater off)

The temperature control set point for the system is adjusted using an adjustment screw

located in side the end of the temperature sensor (near the exit of the electrical wires).

Temperature Error

A second temperature sensor is used to shut down the test fixture if the oil temperature

exceeds the preset alarm temperature. This sensor is connected to input X11 and will

open (input to PLC will go off) when the maximum temperature is exceeded.

If X11 = Off, Turn the pump & heater off, turn on temp fault light, and buzzer. Power to

the unit must be turned off via the ESTOP to reset the fault.

The temperature alarm set point for the system is adjusted using an adjustment screw

located in side the end of the temperature sensor (near the exit of the electrical wires).


Project# 102K15

Document# 9001-0004

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Manual Valve On / Run Pump-Start Switch

PLC POINT Action Comments

X6 Open Valve Sw Switch on panel

X7 Run Pump Sw Switch on panel

Y1 Hyd Valve Closed Energizing Y1 closes valve

Y2 Run Pump

Hydraulic Valve

This is a normally open valve used to dump hydraulic pressure. It should be turned off

anytime a fault is indicated. Energizing this valve turns off flow. De-energizing the

valve dumps the hydraulic pressure.

Output is normally on during any test sequence unless the system is operated manually

using the open valve switch or an automatic sequence is running.

If X6 is on (regardless of mode), turn off output Y1 (i.e. open the valve & dump pressure)

Run Pump-Start Switch

If X7 is on (regardless of mode), turn on Y2 (run pump) as long as switch is held

If X7 is on, start the sequence selected by the mode switch

Pressure Sensor An analog pressure sensor is used to sense the hydraulic pressure. A set point comparator

is used to switch two of the PLC’s inputs at specific pressure settings. Details are as

follows:

Sensor Output:

1 Volt = 0 PSI

5 Volts = 5000 PSI

The set point comparator should be adjusted so that the PLC inputs switch as follows:

Pressure Voltage PLC INPUT Setpoint

Adjustment

PSI < 3050 <4.05 X5 = OFF P2

PSI >3050 >4.05 X5 = ON P2

PSI < 2200 <3.2 X4 = ON P1

PSI >2200 >3.2 X4 = OFF P1


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The programmable logic controller uses these inputs to control the pump pressure and to

measure & indicate the amount of time required to charge the accumulator from 0 psi or

2200 psi to the maximum pressure of 3000 PSI.

Run Mode Switch The run mode switch is used to select the operation mode

Table 1 ~ Run Mode States

Mode X0 X1 X2 X3

0 - Off 0 0 0 0 Pump off (Y2 off), hyd valve closed (Y1 on)

1 – Warm up 1 0 0 0 Runs 0 PSI sequence 1 times and then stops,

stop @ step 8 on 0 PSI sequence. Oil

discharged 4 times. Counts cycles each time

pressure is discharged to 0 PSI.

2 – 2200 PSI

Cycle , CNT

0 1 0 0 Runs 2200 PSI sequence continuously,

counts cycles, , i.e. each time the valve is

opened to relieve pressure is a cycle

3 – 0 PSI

Cycle , CNT

1 1 0 0 Runs 0 PSI sequence continuously, counts

cycles, i.e. each time the valve is opened to

relieve pressure is a cycle

4 – Pump

Only

0 0 1 0 Runs pump to maintain pressure at 3000 PSI

5 – 2200 PSI

Cycle , TMR

1 0 1 0 Runs 0 PSI sequence continuously, at end of

each cycle update the counter in seconds with

the time that it took to charge from 2200 psi

to 3000.

6 – 0 PSI

Cycle , TMR

0 1 1 0 Runs 0 PSI sequence continuously, at end of

each cycle update the counter in seconds with

the time that it took to charge from zero psi

to 3000.


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Document# 9001-0004

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Cycle Descriptions

Table 2 ~ Auto Cycle Sequence for 0 PSI & 2200 PSI

Step Action Description 0 PSI Cycle 2200 PSI Cycle

1 Wait until RUN PUMP

switch (X7) on to start

cycle, Close hydraulic

valve (Y1=ON)

Discharge pressure to => P = 0 PSI P ≤ 2200 PSI

2 Turn on pump until

3000 PSI reached (X5

on) then turn the pump

(Y2) off

Charge pump to 3000

PSI

3 If CTR Mode then

Increment counter (Y4

on for .1 sec per

count), If TMR Mode

then display number of

seconds that pump was

on

Display time or count

4 Wait 5 seconds

5 Open Hyd Valve

(Y1=off) until =>

Discharge pressure to 0

or 2200 PSI depending

on mode selected

45 seconds X4=ON

Pressure=2200

PSI

6 Wait Wait depending on mode 15 seconds 60 seconds

7 Repeat 2 thru 6 a total

of 4 times

8 Wait 4 minutes

9 Go to step 1

Power / Cycle In Progress Light The status of the system is indicated by the Green power indicator.

PLC Output=Y0 (controls light)

System status is as follows:

Power On, no Cycle in Progress = Steady on

Power On and Cycle in Progress = Flashing


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Input / Output Usage The inputs and outputs for the programmable logic controller are summarized in the

tables below: Table 3 ~ PLC Input Usage

X0 BCD Switch - Bit 0




X4 2200 psi

X5 3000 psi

X6 0pen Valve

X7 Start Cycle

X10 Temperature Set Point Sensor

X11 Over Temp Fault

X12 Spare

X13 Spare

X14 Spare

X15 Spare

X16 Spare

X17 Spare

Table 4 ~ PLC Output Usage Y0 Green Light - Power / In Cycle

Y1 Hyd valve on

Y2 Pump enable

Y3 Alarm (buzzer) / Red Light-Temp Fault

Y4 Start Counter

Y5 Reset Counter

Y6 Spare

Y7 Heater On / Red Light - Heater ON

9001-0004 - hyd test fixture - technical reference manual · assembly cooling shroud ... this time...

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