Figure 10-3: Local Network with H201 Ti’s on RS-485 Link
Note the following points:
• The total length of all RS-485 cables must not exceed 1,200m (4,000ft). This
corresponds to an average length of 40m (120ft) for a local network
containing 32 H201Tis.
- From the 201Ti RS-485 link use the existing one shielded pair dedicated to
transmit serial communications.
• Each supervisory link is electrically isolated and protected (2,000V RMS
optocouplers, gas arresters, capacitors and tranzorbs) to withstand at both
ends (H201Ti and H201Ci) surges up to 2,000V RMS as well as the large noise
transients and ground potential differences typically found in electrical
substations.
• Bidirectional data communication is transparently passed by the H201Ti
between the RS-485 port. The communication path is half-duplex (one
direction at a time, from a single talker).
• The maximum distance for an USB link is 5 m (16.4 ft).
The RS-485 cable shall be connected at the following location in the H201Ti: To the
Supervisory Link and Analog Output Termination Board (item 9 in Figure 3-4).
10.3.3 Remote Communications (via Modem)
One or more Hydran 201R Model is and/or Hydran 201i Systems are linked to a host
computer by connecting a modem to a Hydran 201Ci Controller’s DB-9 connector and a
telephone system (private or public); see Figure 10-2.
One or more Hydran 201 Ti can be linked to a host computer by connecting a modem
to a Hydran 201Ci Controller’s DB-9 connector and a telephone system (private or
public); see Figure 10-4.
Note: this type of connectivity is only supported with the Hydran protocol. Modem
connectivity shall be offered in the future Modbus ASCII implementation.
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