BEKA BA574C, Руководство пользователя

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Step 12 Zero adjustment
This adjustment trims the display to
read exactly -10.0
o
C and the output
current to be exactly 4.000mA when the
type J thermocouple is at -10
o
C. This
can be achieved by cooling the
thermocouple to -10
o
C or by inputting
the voltage which the thermocouple
should theoretically produce. If a
voltage is used the transmitter cold
junction compensation (see section
5.3.4) should be turned off during the
calibration, or the input voltage should
be corrected for ambient temperature,
although this may be less accurate.
With the transmitter displaying the
'ZEro' prompt and the correct input
connected to the transmitter, push
P
which will cause the transmitter to
display the thermocouple temperature.
Adjust the display with the
Up and
Down buttons until it is -10.0
Note: Immediately the Up or Down
button is operated the annunicator in the
top left hand corner of the display will
be activated to warn that any change in
the input signal will be ignored while this
display correction is being made.
Operating the P push-button will lock
the transmitter display at -10.0 and
allow the output current to be trimmed
using the
Up or Down button. When the
output current measured by a DVM is
4.000mA, the
E push-button should be
operated to return the transmitter to the
'ZEro' prompt.
This completes calibration at -10.0
o
C.
Step 13 Span adjustment
With the transmitter displaying the
'ZEro' prompt select 'SPAn' by pressing
the
Up or Down button. With the
thermocouple heated to 240 o C, or an
equivalent voltage input, push P which
will cause the transmitter to display the
thermocouple temperature. Adjust the
display with the
Up and Down buttons
until it is 240.0
Note: Immediately the Up or Down
button is operated the annunicator in the
top left hand corner of the display will
be activated to warn that any change in
the input signal will be ignored while this
display correction is being made.
Operating the P push-button will lock
the transmitter display at 240.0 and
allow the output current to be trimmed
using the
Up or Down button. When the
output current measured by a DVM is
20.000mA, the
E push-button should be
operated to return the transmitter to the
'SPAn' prompt.
This completes calibration at 240.0
o
C.
Pressing the E push-button again will
return the transmitter to the display
mode.
8. MAINTENANCE
8.1 Fault finding during commissioning
If the BA574C transmitter fails to function during
commissioning the following procedure should be
followed:
Symptom Cause Solution
No display Incorrect Check wiring
or output wiring or no and power
current power supply supply polarity
Check that voltage
between terminals
5 & 6 is between 10
and 30V with terminal
5 positive.
BA574C Positive The transmitter input
displays 1 display exceeds the upper
over-range operating range of the
selected THC or RTD.
For voltage inputs,
display is incorrectly
calibrated.
Check calibration.
BA574C Negative The transmitter input
displays -1 display is less than the lower
over-range operating range of the
selected THC or RTD.
For voltage inputs,
display is incorrectly
calibrated.
Check calibration.
Output fixed 4/20mA output The transmitter output
below 4mA current over, current is incorrectly
or above or under-range calibrated.
20mA. Check calibration.
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