Number Of Devices Possible On The Fieldbus; Repeaters; Controls And Indications; Actuator Controls - Bernard INTELLIBUS FF Instructions For Use Manual

4.2.4 Number of devices possible on the fieldbus

The number of devices depends of the power supply of the fieldbus. With a supply of 24V
350mA it is possible to connect until 17 actuators (each actuator needs 20mA)

4.2.5 Repeaters

Adding repeaters modules allows to increase both the number of actuator on the line and
total line length. Each repeater allows to lengthen the line by 1900m. See §4.2.2 to know
the possible device number and maximum length for each segment.
According to the type of repeater, it is possible to use until 4 repeaters.
Take also into account the repeater consumption on the fieldbus (usually 30mA).
The important advantage of the repeater compared to other repeater-free technologies is
to keep the communication speed unaffected and therefore to get a very short response
time.
PLC
L. Bernard can supply weatherproof or explosion proof repeaters.

5 CONTROLS AND INDICATIONS

With Foundation Fieldbus system, controls and indications are organized in Function
Blocks. For actuator controls (§4.1) there is Function Block Discrete Output (DO) or
Analog Output (AO). Output is a Fieldbus view: output of the Fieldbus. For actuator
indications (§4.2) there is Function Block Discrete Input (DI) or Analog Input (AI).
These data are mainly use for the Process.
For configuration, setting and maintenance the data are brought together in the
Transducer Block (§5)

5.1 Actuator Controls

Actuator control by Foundation Fieldbus is possible only if the actuator rotating
selector is on the "remote" position.
Conditions which can prevent a command to be
executed:
- Actuator rotating selector on "local" or "OFF".
- Alarm tripped (motor thermal overload)
- Emergency command received (ESD)
Actuators controls are located at the Function Block
Discrete Output (DO) in the INTELLIBUS module.
These controls are:
INTELLIBUS
Instructions for start-up
Segment 1
Number : NR 1157
Revision : B
Repeater
power
supply
Repeater
Segment 2
Remark : If a Function Block
is only one bit writable, then
use DO(1), DO(2),DO(3) to
reach the controls Open,
Close and Stop. In other
case Function Block DO(1)
is sufficient for controls
Open, Close and Stop
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