SNAP POWER SUPPLIES
SNAP PAC R-Series Controller User’s Guide
66
In this guide, SNAP PAC mounting racks are shown in all illustrations.
SNAP PAC mounting racks can hold an I/O processor (brain or rack-mounted controller) and up to 4, 8, 12, or
16 SNAP modules. A SNAP PAC rack is shown below with a SNAP PAC R-series controller installed, but no
modules. All wiring connections are made to the field connectors on the top of each module.
SNAP POWER SUPPLIES
Primary Power Supply
NOTE: For a more general discussion of using power supplies with Opto 22 systems, see the
technical note (form 1271).
SNAP PAC racks use a 5 VDC power source (5 VDC [-0.0, +0.1] at minimum 4.0 amps recommended). For
systems using AC source voltage, the SNAP-PS5 or SNAP-PS5U power supply is recommended. For DC
systems, such as those using DC backup power, the SNAP-PS5-24DC offers DC-to-DC power.
In general, we recommend you
use an independent, isolated, regulated power supply locally with
each rack
. Local isolated supplies offer these advantages:
•
Short supply conductors, which minimize losses
•
Power redundancy, so the failure of a single supply causes only a single rack failure, not a total system
failure
•
Fewer voltage drops and ground loops. (Voltage drops and subsequent ground loops may occur when
power is distributed over a large system.)
Always
use a separate power supply for the field side of the I/O
. Using the rack supply for field actuation
and monitoring defeats the isolation the I/O module offers and therefore increases the chance of a ground
loop within the control system. Additionally, a sudden change of current on the field side can cause
undesirable voltage fluctuations that may interfere with the computer’s operation.
SNAP-PAC-R1-B
SNAP-B4M
SNAP-B8M
SNAP-B8MC
SNAP-B8MC-P
SNAP-B12M
SNAP-B12MC
SNAP-B12MC-P
SNAP-B16M
SNAP-B16MC
SNAP-B16MC-P
sheet (form 0784)
Use these controllers
With these racks
More info
