Wholesale suppliers of Access Control Systems And Gate Operators

Pancho's Tech Tips By Frank Pooley

Using your Multi-Meter

A multi-meter is an indispensable tool in trouble shooting a gate operator system. I recommend a digital meter, as they are easier to use, read, and understand. If you don't have one, get one.

1.       Keep your test leads color coded and untangled. Always use the black lead for the common or ground and the red lead for the voltage or test circuit.

2.     Always double-check the settings of your meter and where the leads are positioned before doing your test. Many multi-meters have very short lives when this step is skipped?

3.       Always use a scale on  your meter that is higher than the level  that you think you will be reading. (Auto-ranging meters do this for you.)

For example:

When testing voltage of a 12-volt solar panel, use the 50-volt scale. 12-volt panels will usually put out 14 to 24 volts in good sunlight. Always keep the black lead in the common or ground terminal of the meter. The red lead will then be placed in one of several receptacles depending on the test being done. Usually a meter will have one place for reading A/C and D/C voltage, continuity and resistance, another position for !ow current amperage (up to 200 to 500 mA) and another for high current amperage (up to 10 or 20 amps.) Testing a Battery: Check battery levels with the charging device removed and the battery under a load.

On our operators,disconnect the solar panel or A/C charger,place your test leads on the battery (20 volt DC scale or higher) andthen activate the operator. Standby voltage is not a good indication of the condition of the battery. You must put a load on the battery and read the voltage at that point. A battery in good condition should not fall below 11.5 - 11.2 volts under load.

5.     Testing current draw:

Determining the current draw of options is important in determining solar requirements and whether an option is working. To test the standby draw of a device, disconnect the power wire to the option (positive). Connect that lead to one of the leads of your meter, connect the other lead of your meter to the positive power source. ! Make sure your meter is set properly for D/C amperage and that the leads are in the correct positions. ! Black lead in the ground receptacle, red lead in the amperage or milii-amp receptacle depending on the current you will be testing, and the meter set to the proper position for that current on the dial.

6.  Testing Continuity:

Continuity testing can check for shorts in wires and broken wires. With your meter set to continuity, touch the  test leads together.
You should hear a tone
and see the reading go to zero or a very low value. This shows you have continuity.
      Example: You have  four wires running 1000' to the gate and want to determine if they are good. First, disconnect the wires at both ends and make sure they do not touch each other or any thing else. Test for continuity between all pairs of wires at one end. The meter reading should not fluctuate during any of the tests. (There should be INFINITE resistance) If it does there is a short between those wires. Second, tie pairs of wires together at one end of the run. Go to the other end of the run and test for continuity on each of those pairs. Every pair should show continuity. If one does not, you have a broken wire.

First, disconnect the wires at each end from the keypad and test for continuity and shorts as in #7. Second, connect one wire from ground (GND) to the key­pad ground (usually black). Third, test voltage going to

II the keypad by connecting a wire to your power (12V) then, test D/C voltage be­tween the red and black wires at the keypad. Next, mn the power to the keypad through your meter as in g6. Depending on the keypad, current should read some­where between 5 to 60 mA. If current is within spec., connect the power lead to the keypad (usually red). Now, program a code into the keypad and test the relay output by placing your me­ter leads on the output of the keypad (usually orange and brown) and look for a conti­nuity reading when you enter the code. If you see continu­ity when the code is entered, then the keypad is working correctly. Connect the or­ange (N/O) lead to INP (trigger) and the brown (Common) lead to GND (ground). Now, when the keypad is used it should function the gate.

Hint! Color coding your wire is VERY helpful in troubleshooting!! I always use red for my positive power, black for my grounds. I then use other colors for my relay outputs. For example, I use Green for my FREE EXITs (green = go), Yellow for my SAFETYs (yellow = stop) etc. When you relate wire color to a function it will make your repairs much eas­ier and faster.

Common current draw of some various options:

Receivers ............... 10 to 20 mA
............ (DKLP) - 35microAmps, others - 20 - 80 mA

Loop detectors ...... (Sarasota DX)- 20 mA, Reno A&E -4mA, others - 150-200mA

Phone systems ......... 150-350 mA or more
633/634 board
.......... 4-10 mA
833/834 board
.......... 18 - 25 mA

A = Amps,

mA = milii-Amps,

uA = micro-Amps

When reading amperage, the scale you are on is very important.

For example:

A 5 watt solar panel, when tested should read between 150 and 350 mA (milii-Amps). If your meter will read milii-Amps this high or higher the display will show 150 to 350. However, if your meter will not read milii-Amps this high, you can switch over to the Am­perage scale and read the number as a decimal. The reading will now be. 150 to .350 Amps. 150 mA =. 150 Amps.

Testing of the circuit board with a multi-meter is also helpfid in troubleshooting. All of the inputs on the board should be 6 volts positive. (Meter on D/C voltage - 20 volt scale, Black lead to any Ground (GND, 9,11, etc...) Red lead to any input (INP, 10, 14, etc...))

Also you can measure the entire standby current draw of your system (provided all options are drawing vower from the board) by discon­necting the Red lead from the battery to the master plug on the board and test­ing the current going to the board. Set your meter to D/ C milii-Amps, place leads in corresponding receptacles, place red lead from board to red lead of meter, place black lead of meter to the positive of the battery.

Read the current. The cur­rent should correspond to the draw of the board and any and all option that are connected to it. For exam­ple, if you have a 633 board (6 mA), multi-code receiver (12 mA), a Sarasota loop detector (20 mA) and a ADV-05 keypad (35 mA) on your system .... you should see approximately 72 mA stand-by current into the board

This Page was updated on 7/27/00

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