D24 Wiring

This topic covers the wiring of the RMC200 D24 Module. See Wiring Guidelines for general wiring information.

The D24 discrete I/O are organized into 4 sections:

Pin-Out

Terminal Block 1 (top)

Terminal Block 2 (bottom)

Discrete Outputs

The D24 discrete outputs are solid state relays. The off state is high impedance, the on state is low impedance (8Ω max, 5Ω typical). Max current 75 mA. Max voltage 30 V.

Outputs can be wired in either a high-side or low-side configuration. Because all the outputs in a group share a common, all outputs in the same group must be wired the same.

The load resistance must be sized such that the maximum current through the SSR does not exceed 75 mA. The maximum current is calculated with the following equation:

Current = Vcc / RLoad

For example, if the supply voltage Vcc is 24V, and the load resistance is 480Ω, the current will be:

Current = 24Ω / 480Ω = 50mA

which is under the 75 mA limit.

Using Outputs with Inductive Loads

External fuses should be used to protect the SSRs if there is a possibility of over-current.  When switching inductive loads, it is important to place a diode or tranzorb across the load to protect the switch when transitioning from an ”ON” to an ”OFF” state. Otherwise, the collapsing magnetic field can cause a reverse voltage spike in excess of the 30 V rating of the SSR.

SSR switching inductive inductive load with high-side configuration:

When calculating the current through the SSR, use the same type of calculation as above, with the coil resistance as the load.

Discrete Inputs

To turn on a discrete input, apply a voltage of the correct level. The polarity is unimportant for inputs 0-19, and is important for 20-23.

Inputs 0-19

The inputs 0-19 are polarity-independent and can be sinking or sourcing. Inputs 0-19 are divided in three groups: 0-7, 8-15, 16-19. Each group shares a common, so all inputs in a group must be wired the same.

Inputs 20-23

Each input is individually isolated and has Din+, Din +5V,  and Din– connections. Use only Din+ or Din+5V, not both.

Example:

Differential Quadrature Wiring without Wire Break Detection

Use these wiring diagrams for encoders with the outputs listed below. The D24 will not be able to detect a broken wire with this wiring configuration.

• 5V Differential

• Differential HTL (High Threshold Logic) for signals from 12V to 24 V

• RS-422*

*RS-422 will only work in this configuration if the differential output is greater than 3.5V. Some RS-422 drivers may not provide sufficient voltage.

Differential Quadrature Wiring with Wire Break Detection

Use these wiring diagrams for encoders with the outputs listed below. The D24 will be able to detect a broken wire with this wiring configuration.

• 5V Differential

• Differential HTL (High Threshold Logic) for signals from 12V to 24 V

• RS-422*

*RS-422 will only work in this configuration if the differential output is greater than 3.5V. Some RS-422 drivers may not provide sufficient voltage.

Single-ended Quadrature Wiring

Use these wiring diagrams for encoders with the outputs listed below. The D24 will be able to detect a broken wire with this wiring configuration.

• TTL

• Push-pull 5V-24V without complements

• Open collector from 5V to 24 V

• RS-422 (3V)* - Connect A+ and B+ in place of A and B in the diagrams. Encoder wires A- and B- remain unconnected.

*Use RS-422 in this configuration only if the differential output is less than 3.5V. Otherwise, use the differential wiring.

See Also

Wiring Guidelines | D24 Module

Send comments on this topic.

Copyright © 2024 Delta Computer Systems, Inc. dba Delta Motion