BEKA BA368C, Руководство пользователя

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To adjust an alarm setpoint select 'SPx1' or 'SPx2'
and press
P which will reveal the current setting.
Each digit of the setpoint may be adjusted using
the
Up and Down push-buttons, and the P button
to move control to the next digit. When the
required setpoint has been entered, pressing
E will
return the display to the 'SPx1' or 'SPx2' prompt
from which the other setpoint may be selected, or
the instrument may be returned to the display
mode by pressing
E again.
Note: Direct access to the alarm and control
output setpoints is only available when the menu is
enabled - see section 4.6.10
4.7 OPTIONAL 4/20mA OUTPUT
The BA368C can be supplied with an optional
4/20mA output which may be programmed to
produce an analogue output proportional to the
whole or part of the speed display. See section
1.9.5.1 for intrinsic safety details.
4.7.1 Programming and adjustment
The main tachometer programme menu is
extended as shown in Fig 4.6 to accommodate the
4/20mA calibration functions.
The ‘4-20 OP’ programme function allows the
4/20mA output current to correspond to any speed
display. e.g. 4mA could represent 0rpm and
20mA 500rpm.
To calibrate the 4/20mA output current, enter the
programme mode by operating the
P and E push-
buttons simultaneously. If the instrument is not
protected by a security code the first parameter
‘Function’ will be displayed. Enter the security
code if the instrument is protected.
Using the Up or Down push button select the
function ‘4-20 OP’ and press P which will result in
the BA368C displaying ‘4.000’, this is the prompt
for setting the speed display corresponding to an
output current of 4.000mA. Pressing
P will reveal
the existing setting with the most significant digit
flashing. The decimal point will be fixed in the
position already defined for the speed display by
the ‘d.P’ function. The value of the flashing digit
may be changed by pressing the
Up or Down
buttons. When this digit is set as required, pressing
P will transfer control to the next digit.
When the required speed has been entered, press
the
E button to return to the ‘4.000’ prompt.
To enter the speed display at which the output
current will be 20.000mA, press the
Up or Down
button to select the ’20.000’ prompt followed by P
to reveal the current setting. This may be changed
in the same way as the 4mA setting. When set as
required, press
E three times to return to the
display mode via the ’20.000’ and ‘4-20 OP’
prompts.
The 4/20mA output may be calibrated to increase
or decrease as the speed display increases, and
most instruments will produce a linear output
between 3.5 and 22mA.
Fig 4.6 4/20mA output programme structure
Note: If the speed display calibration is changed
by adjusting the rotational scale factor ‘r SCALE’,
the timebase ‘t-bASE’, or the position of the
displayed decimal point, the 4/20mA output will
automatically be set to give a constant 3.5mA
output irrespective of the speed display. The
4/20mA output must therefore always be
recalibrated following recalibration of the speed
display.