For small currents up to 2A, PISA11.401 and PISA11.402 are sufficient. When an output close to the maximum 100W NEC Class 2 limit is required, the specially developed PISA11.CLASS2 is the ideal solution.
All outputs on these three PISA modules are classified as "Limited Power Source" (LPS) circuits according to the IEC/EN 60950-1 and therefore meet the requirements for NEC Class 2 circuits. The PISA modules can be supplied by power supplies of any power class. During the event of an overload or system failure, the maximum current is limited for a specific time, subsequently all four outputs on the PISA module shutdown. The outputs can be turned on again by pressing the push button on the front of the module or by applying an external control voltage. The internal protection mechanism in the PISA modules is redundantly designed, meaning that no hazardous situations can arise even in the event of a single fault or an equipment defect.
With the PISA11.CLASS2 module, the maximum output current is automatically adjusted to the supply voltage. This is necessary to obtain the maximum possible NEC Class 2 compliant output power, regardless of whether the supplying power supply is set to 24V, 28V or at the clock-wise end position of the potentiometer. It is of course essential that any adjustment of the output voltage potentiometer does not contradict the requirements of NEC Class 2. The PISA11.CLASS2 module allows a maximum 3.7A at 24V and 3.2A at 28V. This ensures that the NEC Class 2 requirements are always met.