Synrad p250, User Manual, Page: 67 / 106

SAMPLE I/O CIRCUITS PAGE | 67
Sample outputs
P250’s optoisolated, bi-directional switched outputs can drive small loads (50 mA max), PLC inputs, or
relays that can control higher current loads. The following figure illustrates one method of controlling a
remote warning lamp using power supplied by p250’s +24 VDC Auxiliary Power output. Remember to
size current-limiting resistor, R1, so that the current draw does not exceed 50 mA
.
Figure 4-31 p250 output driving warning lamp.
Figure below illustrates a method for controlling a higher voltage, higher current load by using a 24V
control relay. Ensure that the relay coil’s pull-in current does not exceed 50 mA. A diode or surge
suppressor must be installed across the relay coil to prevent voltage spikes from damaging p250
outputs.
Figure 4-32 p250 output driving relay.