rotork Pakscan IIE System Manual page 123

From the cable data and the figures for the maximum permissible resistance and capacitance at each
baud rate the maximum cable distances can be calculated for each baud rate. Note that the loop
distance is the length of the twisted pair cable.
Loop Distance (km) with 1.5mm
Baud Rate
110
300
600
1200
2400
Scanning Time
The time to scan the loop, in seconds, for various baud rates, set up on the master station, with 32
FCU's, (doubling in action) is shown in the table. The times assume that only one field unit has data to
report during the scan.
Scan Time (seconds)
No. of
FCU
60
120
180
240
Command Time
The time taken for each command, from when the master station sends the command to when the
field unit receives it is shown in the table (doubling in action). Commands are interleaved between poll
messages, so a command is actioned almost immediately.
Command Time (milli-seconds)
Baud Rate
2400
1200
600
300
110
The time for the feedback response to the command, e.g. change in digital status resulting from a
motor starting, is:
Commands are sent individually to each actuator. Multiple commands require multiple messages.
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2
cable
60
20.3 km
17.1 km
12.2 km
4.1 km
1.5 km
2400 1200
0.39 0.77
0.89 1.77
1.39 2.77
1.89 3.77
Time (mSec)
27
54
108
216
432
1/2 loop scan time
loop scan time
Publication S177E V2.0 Issue 12/04
Number of FCU
120
20.3 km
15.9 km
11.1 km
2.9 km
0.3 km
Baud Rate
600
1.54
3.54
5.54
7.54
(typical)
(worst case)
Technical Specifications
240
20.3 km
13.7 km
8.8 km
0.6 km
N/A
300 110
3.08 8.4
7.08 19.3
11.08 30.3
15.08 41.2