CHAPTER 4: MAINTENANCE AND TROUBLESHOOTING
SNAP PAC R-Series Controller User’s Guide
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rack. The SNAP equipment is designed with a fail-safe voltage watchdog feature that inhibits operation when
power supply voltage levels get too low, thus eliminating the possibility of unintentional output or input.
Opto 22 offers DIN-rail-mountable power supplies for use with SNAP I/O systems.
Keep in mind that unless you purchase an isolated module, the channels on a SNAP input or output module
are not isolated from one another. Make certain that any transducers or equipment that these modules are
used with are floating, isolated from local earth ground. If the equipment is not floating, make certain that the
two pieces of equipment being connected are at the same ground potential in order to eliminate the
possibility of a ground loop through the module. A ground loop through the module could result in almost
anything, from inaccurate readings to failure of the module.
