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M’Ax User Guide 17
Issue Number: 4
2.7 Types of back-up supplies
The following two types of back-up supply can be applied individually or
concurrently to the Drive. They can continue to be applied when the AC
supply is present.
SLM-and-user back-up supply
This back-up supply primarily supplies the SLM to ensure position
information is not lost in the SLM when the Drive is powered-down
for any reason. A controller communicating by
)
technology will
then be kept updated by the SLM.
The low current demand of an SLM (65mA) makes it practical for a
battery to be used for this back-up supply.
See SLM-and-user back-up supply on the next page.
Auxiliary back-up supply
The auxiliary back-up supply supplies the control circuits in the
Drive, as well as the SLM. A controller receiving simulated-encoder
feedback signals will then be kept updated by the SLM.
Parameters can be accessed and, when suitable connections are
made, the motor can be positioned at low speeds.
This supply can be used also for setting up the Drive without an AC
supply being connected.
See Appendix E Auxiliary Back-up Supply on page 99.
2.8 SLM-and-user back-up supply
Functions
• Maintains the 24V supply to the SLM
• Maintains the 24V user supply output
• Maintains the Drive-status supply
• The 24V supply to the control circuits of the Drive is not maintained
• Low-current requirement (65mA for an SLM and control circuits)
•TheSLM-and-user back-up supply can be at ground potential
•TheSLM-and-user back-up supply can supply one or more Drives,
their SLMs and external circuits, on condition the total current enter-
ing any one Drive does not exceed 500mA
Requirements
The current from the back-up supply to each Drive
must be limited to 500mA by a fuse or other protection
means.
By regulated power supply or battery
Maximum permissible voltage: 28VDC (30VDC including AC ripple
peaks)
Minimum permissible voltage: 17VDC (including AC ripple troughs)
Maximum current: 500mA
Maximum fuse I
2
t-rating: 5A
2
s
A maximum voltage of 22V ensures that when the M’Ax is powered
up no current will be drawn from the supply.
If battery back-up is used, it is recommended that an 18V lead acid
battery is used to ensure the battery is not discharged when the
M’Ax is energised.
Refer to Planning the signal-current consumption (earlier in this chapter)
for each Drive to be supplied by the SLM-and-user back-up supply.
Ensure the supply is able to deliver the total current for the following for
all the Drives:
• SLM and control circuits
• 24V user supply
• Drive-status supply
CAUTION
NOTE
00mA
00mA
00mA
00mA
24V power
supply
+
_
24V power
supply
+
_
STANDALONE
STANDALONE
Back-up supply connected
to an individual Drive
Back-up supply connected
to a number of Drive units
Figure 2-13 SLM-and-user back-up supply connections (these are additional to those shown in Figures 2-3 to 2-12)
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