PASCO ME-8930 SMART TIMER - Manual (Page 11)

012–06734A Smart Timer
7
cleared and the “*” reappears. This RESET-START-STOP sequence is repeated for
each new elapsed time. Whenever the “*” is not showing, the mode may be
changed.
Using the Alternate Timing Function: Connect an appropriate accessory to input
channel #1 or #2. Enter Stopwatch mode and press the Start/Stop key. The Smart
Timer will beep and a “*” will appear on the second line of the LCD. At this time
the accessory will be powered. By blocking and unblocking the beam in the case of
the Laser Switch, or by dropping the steel ball in the case of the Free Fall Adapter,
the elapsed time will be measured. The Smart Timer will resolve 100 microseconds
in the alternate timing mode.
➤ Notes about the Stopwatch Mode:
1. Although it is possible to use older style fences in the alternate timing function to
obtain photogate beam block times, the Smart Timer will provide much higher
accuracy when used with the included fences and the standard timing modes.
2. Two photogates cannot be plugged into the Smart Timer when you are using a
photogate to start and stop the timer. A single photogate can be plugged into channel
#1 or #2 to start and stop the timer. But if two photogates are plugged in, when one
gate is blocked, the other gate immediately is counted as an unblock, and the timer
will display 0.0001 seconds, regardless of the length of time the first photogate is
blocked.
3. You cannot start the timing with the Start/Stop key and end it with a photogate
block or vice versa.
4. If a photogate is plugged in and blocked when you try to use the Start/Stop key as a
stopwatch, the Smart Timer will be timing the photogate and waiting for the
photogate to become unblocked. So when you push the Start/Stop key, the asterisk
disappears and when you push the Start/Stop key again, the asterisk reappears. No
time is displayed until the photogate is unblocked.
Speed Modes
One Gate: In this mode a 1 cm flag passes through the photogate. The Smart Timer
measures the time and calculates the average speed in cm/s.
Collision: In this mode either one or two carts and one or two photogates can be used for
a collision experiment. Once Start/Stop is pressed, the Smart Timer waits for the first
collision and begins timing. The Smart Timer stops timing when two carts have passed
through their respective photogates twice. Timing can always be stopped manually by
pressing Start/Stop and the Smart Timer will display speed(s) based on the information it
has (you will need to press Start/Stop for single cart collisions). The display will present
the results in the following format:
1: xx.x,yy.y
2: xx.x,yy.y
The first number represents the input jack and the following two numbers indicate the
initial speed (xx.x) and final speed (yy.y), respectively.
➤ Hint:
For easier
alignment of the
laser with the
Laser Switch, use
the Test:Gates
mode.
➤ Note:
The stopwatch
function is not a
precision timing
mode and is
therefore most
useful for events
that are longer
than one second.
The accuracy of
the stopwatch is
+/-10
milliseconds.