Communications In A Network, Using An Rs-485 Local Network Link; Table 9-1 - Alarm Relay States, And Status Of The H201Ti, Tdm Signal And - GE Hydran 201 i Instruction Manual

Communications in a Network, Using an RS-485 Local Network Link

Table 9-1 - Alarm Relay States, and Status of the H201Ti, TDM Signal and H201Ci-1
Hydran 201Ti
a
Alarm
ac
Power
Fail
None OK On
H OK On
HH OK On
Fail OK Off
— — —
— — —
— Out Off
a. — = Without consequence; H = High alarm; HH = High-High alarm; Sup. = Supervisory
b. On = Normal (no alarm); Off = Alarm
9.2 COMMUNICATIONS IN A NETWORK, USING AN RS-485 LOCAL
NETWORK LINK
Up to 128 Hydran 201Ti Intelligent Transmitters can be connected in a single network to
be monitored and controlled by computer. Once the H201Ti's are connected to a
Hydran 201Ci-C or Hydran 201Ci-1 Controller via an isolated supervisory link, each
Hydran 201Ci Controller is linked to the next H201Ci in a daisy-chain configuration via an
isolated RS-485 LAN. An example of local network is shown in Figure 9-1 on page 9-4.
Any H201Ci in the network can then be linked to the host computer (see Section 9.3 on
page 9-5). Each H201Ti can communicate with the host computer because each H201Ti is
identified by a specific address (a number from 1 to 254) set by the user.
Note the following points:
• The total length of all RS-485 link cables in a single network must not exceed 1,200 m
(4,000 ft). This corresponds to an average length of 40 m (120 ft) for a local network
containing 32 H201Ci's.
• The RS-485 LAN uses an isolated, three-wire, shielded cable which is protected to
withstand the large noise transients typically found in electrical substations.
Part 17997
a
Sup.
Relays
a
Link
b
H HH
Off Off OK
On Off OK
— On OK
— — OK
— — Broken Fail
— — —
Off Off —
Rev. 6, March 2011
Hydran 201Ci-1
a
TDM
ac
Signal
Power
Fail
Normal OK On
H OK On
HH OK On
Fail OK Off
OK Off
— Out Off
— — Off
a
Relays
ppm
Display
b
H HH
Off Off On
On Off On
On On On
Off Off Off
Off Off Off
Off Off Off
Off Off Off
9-3