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RS422/EIA422
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<< Click to Display Table of Contents >> RS422/EIA422 |
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RS422 this is a 4 wire connection and has a maximum cable length of 1.2 km and a maximum of 10 instrument connections.
All four wires MUST be used. Follow the instrument manufacturers instructions carefully, paying attention to shielding in electrically noisy environments.
The converter will have two Transmit (sometimes called Send) and two Receive connections
These are marked either '+' & '-' or 'A' & 'B' (or both)
| • | In general, the Transmit connections on the converter go to the Receive connections on the instrument. |
| • | In general, the Receive connections on the converter go to the Transmit connections on the instrument. |
| • | In general, the '+' or 'B' connections on the converter go to the '+' or 'B' connections on the instrument. |
NOTE: Most instruments made by Eurotherm Controls DO NOT follow this convention. In most cases connect Converter T+ (or B) to Instrument R-, Converter T- (or A) to Instrument R+ and so on. Please check this in Eurotherm's Instrument Manual.