RM-4DI2-4DO2 Usage Tips

This module is ideal for locations that have only a few signals to monitor and also require some control or annunciator outputs.

Slow / Fast Response – Discrete Inputs

Select fast response for minimal input filtering to respond to DC input changes in 5 mS. Slow response looks for stable inputs for approximately 25 mS to filter contact bounce (important when counting mechanical switch closures) in noisy environments.

Pulse Counters

Enable pulse counters to increment an analog input register (SIXNET address AX0-AX3 or Modbus address 30001 - 30004) each time an OFF to ON transition occurs on the corresponding discrete input (X0 - X3 or Modbus address 10001 – 10004). 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 in the host computer that polls these inputs.

High Speed Counter

The first channel (and only the first channel) may 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.

Driving Inductive Loads with Discrete Outputs

RemoteTRAK discrete output modules have clamping diodes to absorb the turn-off transients that often occur when inductive loads turn off.

High Inrush (Startup) Current in Discrete Outputs

Some devices draw several times their steady state current for a brief period when they are first turned ON. RemoteTRAK discrete output modules are rated to handle this expected inrush. Since this high current only flows for a short period of time, very little heat is generated in the power switches within the module.

Note about Discrete Output Wiring:

All outputs are powered by the same source of power that operates the module. (It is internally connected.) All loads must return to the same ground as the module.

Driving A Heavy Load:

To drive a load that exceeds the 1 Amp rating, or when using a voltage source other than one operating the module, use an interposing relay or power contactor to transfer the control.

Time Proportioned Outputs

Time proportioned discrete outputs pulse ON and OFF with a duty cycle (ON to OFF ratio) that is in proportion to an analog output value assigned to control that output. TPO outputs provide a low cost and high performance method to control heaters and other process variables. Typically the analog output register associated with the TPO is linked to the output of a PID or other control algorithm. Each time proportioned output is cycled ON and OFF quickly to provide smooth control. The maximum ON / OFF time is settable to avoid fluctuations in the process control in accordance with the dynamics of the system. The minimum pulse time is settable for slow reacting power controllers such as mechanical relays and piloted valves.