CAS LP-2G, Service Manual

Page: 48 / 104

12 Self Test Mode
40
< KEYBOARD TEST >
Keyboard Value: 100
Converted (ASCII) Value: 51
Key Name: Q
In our case if we place 60 lb on the platter, the raw counts should be 77624. Now we plug this
into the formula and we get: ( 77624 – 3562 ) X ( 60000 ÷ 74062 ) ÷ 1000 = 60.000 lb. Of course, we
need to round the number to the nearest 2/100th of a pound because the scale’s division at 60 lb is 0.02.
So in this case, 60.000 lb rounds to 60.00 lb.
Another example would be placing 15 pounds on the platter. In this case the raw counts should
be 22077. Using the formula we get: ( 22077 – 3562 ) X ( 60000 ÷ 74062 ) ÷ 1000 = 14.999 lb. Again,
we need to round this number but this time to the nearest 1/100th of a pound because the scale’s
division at 15 lb is 0.01. So in this case, 14.999 lb rounds to 15.00 lb.
NOTE: You may find the Span Fine Adjust screen a bit more useful for testing the load cell. This screen
shows the weight in 0.001 lb divisions; however, the display update rate is low so the weight display
appears sluggish. You simply need to wait a few more seconds to see the weight fully stabilized.
12.4 Keyboard Test
At the Self Test Menu
screen, press the 3 key for
Keyboard Test. The Keyboard Test
screen will be displayed.
Keyboard value: This value is in
hexadecimal and corresponds to
a key’s hardware scan code.
See the keyboard table (next
page.)
Converted Value: This value corresponds to a key’s ASCII value. It only applies to the QERTY keyboard
and the numeric keys. All ASCII values generated by other keys are ignored.
Key Name: For most keys this should be the same as the words or symbols that appear on the key.
You can use this test to see if there is a problem with the keyboard. If you press a key and it does
not generate a response on the screen, then you know that switch may be broken. Another possibility
is that two different keys may generate the same Keyboard value. In this case you may have a short in
the keyboard. Notice that even the 2 SPACE keys have different Keyboard values.
The table is arranged in the same order as the scale’s keyboard. Some keys are not shown with
their key names because these keys are not keys from the standard QWERTY keyboard. The shaded
keys are from the standard QWERTY keyboard.
Although some key functions can be disabled, this does not mean that the key is disabled;
therefore, all keys should illicit some response in this test mode.
( Raw Counts – Current Zero ) X ( Resolution ÷ Span Value ) ÷ 1000 = Weight
Where
Resolution
= to 60000 for 60 lb, 30000 for 30 kg or lb, 15000 for 15 kg