OPTO 22 Optomux B1, User Manual

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CHAPTER 3: INSTALLATION AND WIRING
B1 and B2 User’s Guide
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Power Requirements
DC power must be provided to each Optomux unit. All B1 and B2 boards r5 volts DC (±.1
VDC) at 0.5 amps.)
B2 analog units also r15VDC and -15 VDC (±.25 VDC). The amount of power required is
dependent upon the type and number of analog I/O modules that are plugged into the unit. The B2
re15 and -15 volts at 10 milliamps. Power requirements for analog modules are included in
the module specifications. To determine what size power supply is needed, add the requirements
for each module to the 10 milliamps required by the Optomux mounting rack.
Analog racks also provide terminals for a se24 volt supply to be used when powering a 4 -
20 mA loop using 4 - 20 mA analog I/O modules. For this type of application, the +24 volt supply is
required in addition to the supplies mentioned above. Refer to the module’s data sheet for
information on wiring AD3 and DA3 modules with a loop supply.
The current requirements given for the output modules are only for the modules themselves. Load
requirements must be added to these to determine total power supply requirements.
Although it is possible to distribute DC from a common power supply to several locations, better
noise immunity is obtained by having separate power supplies at each physical location where an
Optomux unit is installed.
A +5 VDC power supply option can be used to provide power to digital Optomux units. The power
supply attaches to the I/O mounting rack beneath the removable brain board portion of the
Optomux unit.
Connecting the Power Supply
Connect the 5-volt power to the barrier strip connectors marked “+ 5V” and “GND” on the mounting
rack. If the + 5 volt supply is to be used by more than one Optomux unit or other devices, make sure
there is 5 VDC (± .1 V) at each set of terminals on each rack. The communications wiring and the
+5-volt and ±15 volt wires should be routed away from any high-voltage field wires. There should
only be one “earth” ground connection per network, typically connected at the host site. If the
“earth” ground connection is at the host site, make sure none of the supplies is connected to “earth”
ground. This method of grounding prevents ground loop problems due to offset voltages appearing
between multiple ground points.
If an Opto 22 PBSA/B/C power supply is used with the digital racks, the + 5 VDC logic connection is
made by the supply when it is screwed to the rack. In this case, the only connection to be made is
the 120 VAC (220 VAC or 10-28 VDC depending on supply type) connection to the PBSA (PBSB or
PBSC) supply.
Separate or co and - 15 VDC (±.25 VDC) supplies can be used to provide power to analog
I/O modules. If using combined supplies, make sure that the 5 VDC RETURN line is separate from the
15-volt COMMON line. Otherwise, the isolation of the analog modules will be defeated.
CAUTION: Check polarities of all power supply connections before applying power to the Optomux unit.
Incorrect polarity may cause damage to the unit.