ET-16DI2 Usage Tips

Sourcing or Sinking Discrete Inputs

Sourcing inputs switch the source of power (typically +24 VDC). When an input is ON, power is applied to the input terminal. This is the most common situation. Sinking inputs are ON when a ground condition is present. EtherTRAK discrete inputs are set at the factory to accept sourcing inputs. To configure discrete inputs as a group to accept sinking (ground seeking) logic, remove the module from its wiring base and open the access door in the base. Set the movable jumper to the "-" (sinking) position.

Slow / Fast Response – Discrete Inputs

Select fast response for minimal input filtering to respond to DC input changes in 2 mS. Slow response looks for stable inputs for approximately 25 mS to filter contact bounce (important when counting mechanical switch closures), in noisy environments, or when reading AC inputs.

Pulse Counters

Enable pulse counters to increment an analog input register (SIXNET address AX0-AX15 or Modbus address 30001 - 30016) each time an OFF to ON transitions occurs on the corresponding discrete input (X0 – X15 or Modbus address 10001 - 10016). These counters report unsigned 16 bit values (0 - 65535) and are volatile (forget their counts if power is lost). These counters cannot be reset under software control. Typically, retention of the values and resetting the counts is accomplished in software running in the host computer that polls these inputs.

High Speed Counter

The first channel (and only the first channel) can be configured as a high speed counter to record pulses as fast as 2 KHz. In this high speed mode, the input filtering is not active, and even short input spikes will most likely be counted.