BEKA BA364G, Manual

Page: 18 / 40

6.4 Input:
inPut
The Input function contains two sub-functions
inP . tYPE
and
dEbounCE
that define the type of input
and the amount of input noise rejection.
6.5 Input type:
inP. tYPE
inP . tYPE
is a sub-menu in the
inPut
function which
defines the type of input transducer or input pulse
that the instrument will count. To check or change
the type of input, select
inPut
in the configuration
menu and press
(
which will reveal the
inP. tYPE
prompt, pressing
(
again will show the existing
Input setting . If set as required press
)
twice to
return to the configuration menu, or repeatedly press
the
&
or
*
button until the required type of input is
displayed and then press
)
twice to return to the
configuration menu.
One of following six types of input may be selected:
Switching
thresholds
Low High
oP . CoL
Open collector
2
2 10k Ω
VoLt5 L
Voltage pulse low 1 1 3V
VoLt5 H
Voltage pulse high 1 3 10V
CoiL
Magnetic pick-off 0 40mV
Pr . dEt
Proximity detector 2 1.2 2.1mA
ContACt
Switch contact
2
100 1000 Ω
Notes:
1. Maximum voltage input +28V.
2. For transducers connected to the input that
require energising i.e. proximity detectors,
switch contacts or open collector transducers,
terminals 3 & 4 of the BA367NE should be
linked together.
3. To count correctly, the input pulse must fall
below the lower switching threshold and rise
above the higher switching threshold.
4. See section 6.6 for maximum counting
frequency.
6.6 Input debounce:
dEbouncE
dEbouncE
is an adjustable sub-menu in the
inPut
function which prevents the input miscounting when
the input pulse has noisy edges, such as those
resulting from a mechanical contact closing and
bouncing.
Three levels of protection may be selected. The
amount of debounce applied depends upon the type
of Counter input that has been selected in the
inP . tYPE
function.
Select
inPut
in the configuration menu and press
(
which will reveal the
inP . tYPE
prompt, press the
&
or
*
button to select
dEbouncE
followed by
(
to reveal the existing setting. Pressing the
&
or
*
button will scroll through the three levels. When the
required level has been selected, pressing
)
twice
will enter the selection and return the display to the
configuration menu.
The following table shows the minimum time that the
input pulse must be continuously above the upper
input switching threshold and continuously below the
lower switching threshold to ensure that the Counter
processes the input pulse. Input switching
thresholds are shown in section 6.5.
debounce
level
Min input pulse width
Type of Input
Contact All others
Default 1600µs 40µs
Heavy 3200µs 350µs
Light 400µs 5µs
The maximum counting frequency of the BA367NE
depends upon the debounce level selected, the
shape of the input pulse and its amplitude. The
following table assumes a square wave input and is
included for guidance. The maximum counting
frequency will be lower if the input pulses have
sloping edges and the pulse amplitude only slightly
exceeds the input switching thresholds.
ONLY FOR GUIDANCE
debounce
level
Max counting frequency
Type of input
Contact All others
Default 250Hz 12kHz
Heavy 120Hz 2kHz
Light 1000Hz 100kHz
The minimum counting frequency is 0.01Hz. Below
this frequency the rate display is forced to zero.
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