Appendix G - Kit Assembly Procedure

* Tip:  Add components from shortest in height to the tallest.
* The author can assemble and test 1 sensor in about 10 hours or 3 sensors in about 20 hours. You are probaly faster B-)

1. PCB Preparation for Case Mounting

[ Approximately 30 minutes ]

A. Mount the PC Board in the case. Use a roto-tool or rat tail file to grind a radius in the board edge to allow screw clearance. There are small crescent etchings on the PCB marking where the radius clearance may be needed.

B. For a case bottom reset pin hole: mount the PC Board in the case and use the center hole in the Reset Button SW1 as a drill guide to drill a hole in the case bottom. Enlarge the case hole if desired.

C. Remove the PCB from the case mounting to complete the PCB assembly

2. Solder in the Sockets

[ Approximately 30 minutes ]

U2 – 8 Pin Socket

X1 – 8 Pin Socket; Only Pins 1,4,5, and 8 are used. Trim off Pins 2,3, 6, and 7.

U6 – 18 Pin Socket

U1 – 28 Pin Socket

3. Solder in the Pin Headers

[ Approximately 30 minutes ]

J1 x 6

J2 x 2

J3 x 2

J4 x 3

J5 x 3

J8 x 3

J9 x 3

J10 x 10

J11 x 3

J30 x 3

CLK x 1 - Do this one last to prevent pushing it through when hot

4. Solder in the Bypass Capacitors

[ Approximately 30 minutes ]

5. Solder in the Diodes

[ Approximately 30 minutes ]

6. Solder in the Resistors

[ Approximately 60 minutes ]

7. Solder in the VAC and Battery Connectors

[ Approximately 15 minutes ]

8. Solder in the LEDs

[ Approximately 15 minutes ]

9. Solder in the Electrolytic Capacitors

[ Approximately 15 minutes ]

C17 - 10uF

C21 - 22uF

C20 – 470uf

10. Solder in the Voltage Reference and Voltage Regulator

[ Approximately 15 minutes ]

Trim the Voltage Regulator Heat Sink fins to clear the bypass jumper, J3.

Install Jumpers J3, J5, J11

Install the Voltage Regulator Heat Sink.

11. AC-AC Transformer Connector and Cable Sub Assembly

[ Approximately 30 minutes ]

Solder the 2.1mm case connector to the power cable that connects to J7

12. Power Supply and Voltage Reference Verification Test

[ Approximately 15 minutes ]

Connect the VAC transformer and test the +5 VDC and +2.5 VDC on the J30 pins. If you get these values and no smoking components, then you are ready to install the oscillator and ICs!

13. Install the ICs

[ Approximately 15 minutes ]

U1 – dsPIC30F3013 Micro Controller

U2 – MCP6292 Operational Amplifier

U6 – MAX232A* or MAX242A**

* Note: The MAX232A has 16 pins and the socket is 18 pins. When using a MAX232A, insert the IC with the MAX232A Pin #1 in the 18 pin socket's Pin #2 position. With a MAX232 installed, the socket pins #1 and #18 are empty.

** Note: The GridTrak PMU design includes support for the MAX242 to enable resetting the RS232 transceiver if this is required for improved interfacing with GPS devices.

14. Final Assembly Power Check

[ Approximately 15 minutes ]

Connect the AC-AC Transformer and test the +5 VDC and +2.5 VDC on the J30 pins.

16. Case Machining

[ Approximately 120 minutes ]

Remove the PCB from the case.

Cut holes in the case for the 2.1mm VAC Transformer Jack and the DB9 RS232 connector. Make sure to position the hole locations to allow clearance for the inside case posts. I personally think that cutting the hole for the DB9 RS232 connector is the most challenging task of the sensor assembly!

17. Assemble the Transformer Power Supply Connection

[ Approximately 15 minutes ]

Trim the Connector Plug Wire Leads from the J7 to the 2.1mm VAC Transformer Jack to a convenient length and solder them to the Jack. This is an AC connection so only wire up the Jack's inside pin and spring contact. Do not connect the panel ground outside of the Jack to the wiring. Mount the Jack in the case. Do not run the wires near the voltage regulator heat sink.

18. Assemble the DB9 RS232 Connection

[ Approximately 30 minutes ]

If the DB9 Connector is going to be mounted close to the RS232 pin headers, then cut 2 of the 7” blue F-F jumper wires in half and solder the cut ends into the DB9 Connector's # 2, 3, and 5 solder cups.

Mount the DB9 Connector in the case using the 4-40 screw posts, lock washers, and nuts.

19. Mount the Reset Button

[ Approximately 15 minutes ]

Mounting the Reset Button on the top of the board is better for open case testing or operation of the sensor. Mounting the Reset Button on the bottom of the board enables it to be clicked through the pin-hole in the bottom of the case. There also is a Reset connector next to SW1 that can be used to wire up an external Reset Switch.

During normal power up and operation, the sensor does not require the Reset Button.

The Reset Button has spring formed legs. It can be inserted into the PCB and will stay in place with soldering for testing purposes if you have not decided on top or bottom placement or want to try both before permanent soldering the button in place.

20. Mount the PCB in the Case

[ Approximately 15 minutes ]

Mount the PCB in the case.

Connect the Transformer Jack assembly's plug to J7.

Connect the RS232 wires to the RS232-1 header pins.

Wire from DB9 # 5 connects to RS232-1 Header Pin #1

Wire from DB9 # 3 connects to RS232-1 Header Pin #2

Wire from DB9 # 2 connects to RS232-1 Header Pin #3

22. Optional Battery or Alternative 9VDC Power Wiring

[ Approximately 30 minutes ]

Solder the J6 plug wires to the battery connector or alternative 9VDC power supply components or switches per your own custom requirements.

21. The PMU is Now Ready for Use

[ Approximately 30 minutes ]

Put your tools away and clean up the mess you made!

Last edited Feb 10, 2011 at 8:39 PM by ajstadlin, version 4


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