5.RS485 SPECIFICATIONS
MIUXXXX/485 are
Features: | Point to Point | or Multidrop/Multipolling |
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| Full or Half Duplex |
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| Drivers are short - circuit current limited | & protected against excessive | ||||||
| power |
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| dissipation (shutdown will places the drivers in a high - impedance state). | |||||||
| When Drivers are disabled (by TXD), | drivers | will switch to | high | ||||
impedance | state. |
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| Note in | |||||||
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| Receiver input impedance is 12K ohms. |
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| Reduced slew- rate drivers that minimize EMI and reduce reflections | |||||||
caused | by improperly | terminated cables |
| This | will | allow | error - | free |
transmitted | data up to 200Kbps |
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| RS485/RS422 | standard covers line | lengths | up to | 4000 | feet. For | line | |
lengths |
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| greater than 4000 feet a line repeater | can be added. |
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| MIUXXXX/485 can drive 4000 feet | of 26AWG twisted - pair cable at | ||||||
| 200k bps into 120 ohms load. |
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To minimize reflections, the line should be terminated at both ends. In multi - polling/multi - drop environments (up to 32 drops) all drops off
themain cable should be as short as possible.
Only the Master/Host unit and the end of cable unit should be terminated.
Typical Speed versus Distance -
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| SPEED | DISTANCE |
| 1200bps | 6.0 miles(9.6 km) |
| 2400 bps | 4.5 miles (7.2 km) |
| 4800 bps | 4.0 miles (5.5 km) |
| 9600 bps | 2.5 miles (4.0 km) |
| 19,200 bps | 1.8 miles (2.9 km) |
| 38,400 bps | 1.4 miles (2.1 km) |
| 56,400 bps | 1.1 miles (1.8 km) |
| 115,000 bps | 0.6 miles (0.9 km) |
NOTE: Speed and distances will depend on actual operating environment.
6. ENVIRONMENTAL SPECIFICATIONS
The CIU/485 (MIUXXX\485) meets the following environmental specifications.
Install Op and Diags for MIU Modems and RS485 | Page 5 of 16 |