The RB12 contains a differential RS422 receiver input with selectable termination, and two differential RS422 line driver outputs. Each output is capable of driving one RS422 input with 100 ohm termination or two RS422 inputs with input termination of 200 ohms each.
Use two RB12s to buffer the RS422 signals from a quadrature encoder (one RB12 for A and one for B) to allow a gearing encoder to be used with multiple motion controllers.
Simply snap off the side panel of the RB12’s DIN rail mount enclosure to access the termination jumper.
Features
- Connect multiple motion controllers to one encoder for gearing applications
- RS422 differential transceivers for high noise immunity
- Selectable termination on RS422 input—high impedance or 220 ohm
- Compact DIN-rail mount
- Single +5VDC ±5% power supply
- Low current draw—30mA typical (varies with termination impedance of RS422 load(s) on the RB12 outputs)
Specifications
| Buffer | Number of Inputs | 1 |
| Input Type | RS422 differential receiver (MAX490 or equivalent) | |
| Input Impedance (From Input + to Input -) | Selectable--High (>6 kohms) or Low (220 ohms ±7%) | |
| Input Differential Threshold Voltage | -0.2 to +0.2 Volts | |
| Number of Outputs | 2 | |
| Output Type | RS422 differential line driver (MAX490 or equivalent) | |
| Poutput Drive | Drives 100 ohm to 250 ohm RS422-type input(s) | |
| Speed | 2.5 Mbps (see MAX490 datasheet for details) | |
| Power Supply Requirements | Power Supply | Single +5VDC ±5% |
| Current Requirements | 30mA typical (varies with impedance driven by RB12—RB12 draws less than 3mA unloaded) | |
| Isolation | Not isolated—all commons (Input, Output, and Power Supply) are tied together | |
| Mechanical | Dimension | 0.7 x 2.45 x 2.5 in (18 x 62 x 65mm) (W x H x D) |
| Mountings | Mounts directly to DIN rail |
RB12 Wiring
| Terminal | Function |
|---|---|
| A | + RS422 Output (1) |
| B | - RS422 Output (1) |
| C | + RS422 Input |
| D | - RS422 Input |
| E | + RS422 Output (2) |
| F | - RS422 Output (2) |
| G | Common |
| H | + 5 VDC Power Supply |