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9. DIAGNOSTICS
9.1 Preliminary checks
I.
Check whether the input/output wiring and/or extension cables are properly connected on the FX
4AD-PT analog special function block.
II. Check that the PLC system configuration limits have not been exceeded, i.e. the number of special
function blocks, and the total system I/O are within the specified range.
III. Ensure that the correct operating range has been selected for the application.
IV. Check that there is no power overload on either the 5V or 24V power sources, remember the loading
on main unit or a powered extension unit varies according to the number of extension blocks or
special function blocks connected.
V. Make sure that the main unit has been switched to RUN.
9.2 Error checking
If the FX
-4AD-PT special function block does not seem to operate normally, check the following items.
2N
•
Check the status of the POWER LED.
Lit
:The extension cable is properly connected.
Otherwise :Check the connection of the extension cable.
•
Check the external wiring.
•
Check the status of the "24V" LED (top right corner of the FX
Lit
:FX
2N
Otherwise :Possible 24V DC power failure, if ON possible FX
•
Check the status of the "A/D" LED (top right corner of the FX
Lit
:A/D conversion is proceeding normally.
Otherwise :Check buffer memory #29 (error status). If any bits (b0, b2, b3) are ON, then this is why
the A/D LED is OFF.
10.EMC CONSIDERATIONS
Electromagnetic compatibility or EMC must be considered before using the FX
Mitsubishi recommend that the PT 100 sensors used, should be fitted with a form of seild or screening as
protection against EMC noise.
If some form of cable protection is used, the "Shield" must be terminated at the
as shown in section 4.1.
Because of the delicate nature of all analog signals, failure to take good EMC precautions could lead to
EMC noise induced errors; up to ±10% of actual values. This is an absolute worst case figure, users who
do take good precautions can expect operation within normal tolerances.
EMC considerations should include selection of good quality cables, good routing of those cables away
from potential noise sources.
Additionally it is recommended that signal averaging is used as this will reduce the effects of random noise
"spikes".
This manual confers no industrial property rights or any rights of any other kind, nor does it confer any
patent licenses. Mitsubishi Electric Corporation cannot be held responsible for any problems involving
industrial property rights which may occur as a result of using the contents noted in this manual.
HEAD OFFICE : TOKYO BUILDING, 2-7-3 MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN
HIMEJI WORKS : 840, CHIYODA CHO, HIMEJI, JAPAN
-4AD-PT is ON, 24V DC power source is ON.
Manual number : JY992D65601
Manual revision : E
Date
-4AD-PT).
2N
-4AD-PT failure.
2N
-4AD-PT).
2N
: September 2007
-4AD-PT.
2N
FG
terminals
-
2N
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