Siemens ST950 Plus+ - Page 139

ST950 Plus+ User Manual
ST950 Plus+ User Manual
Page 139 of 176
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Check the +24V DC output from the PSU. If it is not present, remove the power plug into the CPU
Card and re-test – if it is then present, then suspect a short-circuit between the PSU and the I/O
cards.
Remove the high-speed serial cables in the controller to isolate the short-circuit.
If there is no +24V DC available at the PSU, then check the AC mains input to the PSU. If present,
replace the PSU and re-test.
If the lights are out on only one I/O card, then the power supply on that card may have failed –
replace the card and re-test.
9.3.7 Power Bank (Redundancy Module and 48V PSU)
If the fault log indicates an issue with 48V supplies or has raised any issues with the redundancy
module, Table 16 below is a useful guide to diagnostics.
If the Green LEDs, which are indicators for up to three PSUs, are on then the supply is functional.
Otherwise check the 48V PSUs to confirm performance.
Led Indicator
Function
Meaning
Green x 3
Presence
On
Energised PSU is
connected.
Yellow 1
Imbalance LED
On
19
Voltage Imbalance
between PSU 1 and 2
Yellow 2
Imbalance LED
On
20
Voltage Imbalance
between PSU 2 and 3
Red x 3
Overload
On
Too much current is
being drawn from a PSU
Table 16 – I/O Card LEDs
The 48V PSUs can easily be confirmed as operational as they have a ‘DC_OK’ LED indicator.
Also see additional details in section 3.7.4.
9.3.8 Intelligent Backplane Controller
If all LEDs on the card are out, then follow the same checking as for the I/O card.
19
Solving an Imbalance issue involves the careful adjustment of the connected PSUs. Please
contact Siemens Engineering in Poole for assistance before attempting any adjustment.
20
Flickering - lightly loaded systems may show one or more flickering Imbalance LEDs this is not a fault.