24VDC Sink Discrete Input Model No :- 621-3560R Number Of Inputs :- 16 per module Points per Common :- 16(-VDC) Voltage Range :- 18-28VDC Current Range :- 6-15mA The 'R' suffix indicates the module can be removed or inserted into an I/O rack while the rack remains powered. Other I/O modules in the rack continue to control the machine or process.