BEKA BA368C, Руководство пользователя

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2.9 CALIBRATION EXAMPLE
A BA368C is required to display the position and
speed, including direction, of a cable which is
sensed by two proximity detectors mounted on a
wheel with a circumference of 1m over which the
cable runs. The sensors, which produce fifteen
pulses per revolution, are positioned so their
outputs are electrically 90
o
apart. The BA368C is
required to display the position of the cable relative
to a starting point in metres with a resolution of
0.1m, and to show speed of the cable in metres
per second with a resolution of 1m. The total
display (position) is to be resettable by an external
contact, not from the BA368C front panel. To
prevent tampering the instrument programme
menu is to be protected by security code 1209
The BA368C may be calibrated on-site without
disconnection from the power supply or from the
two proximity detectors.
Step 1 Enter the programming mode
Put the BA368C in the programming
mode by simultaneously pressing
P
and E. Assuming a security code has
not already been entered the
instrument will respond by displaying
‘FunctIon’ which is the first parameter in
the main menu. See Fig 2.3
Step 2 Select the instrument function
With ‘Function’ displayed, press P to
reveal the existing instrument function.
If this is not ‘CountEr’, select ‘CountEr’
using the
Up or Down button. To
prevent accidental changes the new
setting will only be executed after the
pass word ‘SurE’ has been entered.
Press P which will produce a display of
‘Set nO’ with the ‘nO’ flashing. Using
the
uP or Down button change ‘nO’ to
‘YES’ and press P again which will
result in a display of ‘0000’. Using the
Up or Down button to adjust each digit
and the P push-button to transfer
control to the next digit, enter the pass
word SurE.
Note: S is entered as 5.
Finally, press E which will execute the
function change and return the
instrument to the ‘FunctIon’ prompt in
the main menu.
Step 3 Select the type of inputs
Using the Up or Down button scroll
through the main menu until ‘InPut A’
is displayed; press P to reveal the
existing setting. Using the Up or Down
buttons select ‘Pr.dEt’, the input for a 2-
wire proximity detctor, and then return
to the 'InPut' prompt in the main menu
by pressing
E .
Repeat for the second input ‘InPut b’
Step 4 Select input count mode
The two proximity detectors are
positioned so their outputs are
electrically 90
o
apart. From this
information, in the quadrature input
mode the BA368C can sense the
direction of wheel rotation. Hence, the
relative position of the cable can be
displayed
Select ‘Count’ from the main menu and
press
P . Using the Up or Down button
select ‘A rEL b’ the quadrature function
and press
E to return to the ‘Count’
prompt in the main menu.
Step 5 Counting edge
The proximity detector current rises
when it detects a marker on the wheel.
The BA368C is therefore required to
count when the proximity detector
current changes from low to high i.e. a
rising edge.
Select ‘Cnt EdGE’ from the main menu
and press
P to show the existing
setting. Using the Up or Down button
select '‘EdGE 2'’ followed by E to enter
the selection and return to the main
menu.
Step 6 Activate lower rate display
A rate display is required so the lower
display must be activated.
Select ‘dISPLAY.2’ from the main menu
and press
P to show the existing
setting. Using the Up or Down button
select 'On’ followed by E to enter the
selection and return to the main menu.
Step 7 Position of decimal point
In this example the BA368C is required
to display total (position) with a
resolution of one decimal place and
rate (speed) with no decimal point.
Select ‘d.P.’ from the main menu and
press
P . The display will be activated