RI-CTL-MB2B-30 Datasheet, PDF (20/40 Pages) Texas Instruments – Series 2000 Reader System

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Power Supplies
2.5.2 Non-Regulated DC Power Supply (Without Memory Backup)
If a non-regulated DC Power Supply is used to supply the Control Module logic circuits, it should be
connected to the reader as shown in Figure 2-5. Jumper JP6 must be closed.
Figure 2-5. Non-Regulated Power Supply
2.5.3 Regulated DC Power Supply (Without Memory Battery Backup)
If you use a regulated (5 V) Power Supply for VCC2, it should be connected to the reader as shown in
Figure 2-6. Jumper JP6 must be removed.
Figure 2-6. 5V Regulated Control-Logic Power Supply
2.5.4 Battery Backup for Memory
Even though the Series 2000 Control Module remains powered, it is possible the memory contents may
be erased when the Control Module is reset. This occurs when power is temporarily removed from the
RAM during reset.
A reset can be initiated in one of three ways:
• Internally by the reset/watchdog circuit
• Externally by using the reset input (pin 3 of ST33)
• Externally by the RS-232 DTR signal (RI-CTL-MB2B version only)
In order to prevent memory contents being lost during a reset, we recommend that the following
precautions are taken:
• Connect VCC2 (pin 5 of ST22) and VCC3 (pin 6 of ST22) to each other.
In order to prevent memory contents being lost during a power-down, or during a reset, we recommend
that you take the following precautions:
• Connect a battery (with VCC3 nominally 3.0 V) between pins 6 (+) and 7 (–) of ST22 as shown in
Figure 2-7, instead of a bridge between VCC2 and VCC3. Tolerances for the battery are given in
Section 3.2.1.1.
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Installation
SCBU044 (11-09-21-077) – January 2008
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