Toptech MultiLoad III Installation Manual page 30

CHAPTER 4– DATA COMMUNICATIONS INTERFACE
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2-wire, one twisted pair with overall shield.
- 30 pF maximum between conductors.
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1,000 ohm impedance.
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Maximum length: 4,000 feet (1,220 Meters).
- Maximum stub length: 15 feet.
All exposed shields must be properly insulated to prevent short circuits.
All shields must be continuous, soldered, and properly insulated.
RS-232
The RS-232 protocol is designed for point-to-point (i.e., computer to a single device)
communications limited to 50 feet requiring a minimum of 3 wires: transmit, receive, and ground.
Additional wires are required for hardware handshaking when using printers and data loggers.
Wire used must meet the following characteristics:
- 24 AWG.
- 3 conductors with overall shield (data only) or 8 conductors with overall shield (full
handshaking).
- 30 pF maximum between conductors.
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MultiLoad III/RCU III Hardware - Explosion Proof (EX) Installation Guide