1756-DHRIOK Data high-speed/remote I-O communication module You can have up to 32 Logix connections

Manufacturer: Rockwell Automation
Brand: Alan Bradley
Part Number/Catalog Number: 1756- De Rio
Series: ControlLogix
Module Type Data high-speed/remote I-O communication module
The Allen-Bradley 1756-DHRIO is a ControlLogix Data Highway Plus/ Remote I/O communication interface module. The module has two (2) channels and supports communication rates of 57.6 kilobits per second, 115.2 kilobits per second and 230.4 kilobits per second, depending on cable length. It can transmit messages through up to three chassis and four communication networks. Using this module, information can be exchanged between devices such as PLCS, SLCS and ControlLogix controllers, even on different networks.

It supports the following types of communication: remote I/O, Control and Information Protocol (CIP) messaging, and Data Highway Enhanced (DH+) messaging between devices. It can have up to 32 Logix connections, and remote I/O links can connect to remote I/O devices as well as other smart devices. When connected to a remote I/O network, it can act as an adapter or scanner, transferring analog, digital, block, and professional data even without message instructions. Before installing the 1756-DHRIO module, you will need to program the network type switches for each channel and install and connect the ControlLogix power supply and chassis. You can install as many modules as you want in the same case, but it depends on your available power supply. Note that the module can be installed or removed even when the case power supply is applied, but you need to follow safety precautions, especially if the area is harmless and the power supply is removed, to prevent arcing from causing excessive wear on the contacts of the module and connector. Be sure to release potential static electricity, as modules are sensitive to electrostatic discharge.

The RIO and DH+ protocols use the same cable type. The recommended cable is the Belden 89463 two-axis cable, 0.52 mm² (20 AWG), rated at 200 °C (392 °F). The suitable alternate connector is the Phoenix terminal, part number MVSTBR2.5/3-ST BK AU.

DH+ and remote I/O networks require the use of terminal resistors because it follows the Daisy chain topology. The resistor is installed on the first and last node of the network. The resistance value depends on the network speed. 82 ohms are used for a network speed of 230.4Kbps. 150 ohms are used for network speeds of 57.6Kbps or 115.2Kbps. Other considerations are also taken into account, including the type of device connected to the network. Terminal resistors are installed on lines 1 and 2 of the cable. The third cable is a shielded cable.