Pakscan IIS Technical Manual Issue 1.0
Publication S130E 57
9.3 Loop Data
In Section 7.4 the various pieces of information relating to the loop wiring and the cable parameters were
measured and recorded. When it comes to setting the Master Station Loop Data the Loop Speed has to be
compatible with that data (also the individual field units must be set to match the Master Station setting). The
following table indicates the Loop Baud Rate that may be used for various values of cable resistance and
capacitance.
Pakscan Cable Tolerances
You should not attempt to run the system with cable resistance and capacitance values above those
specified for the chosen baud rate as communication may not be possible.
To set the loop parameters, start from the Top Setup Menu (as shown in section 8.5.1). If the Ports have just
been set then this is the screen displayed.
Press '3' to select Loop Options.
The screen revealed is as shown in section 8.5.3 of the Manual.
Press '1' to step around the available baud rates, when the correct
one is revealed leave it there.
Press '2' to set the number of the highest address for the connected field units on the loop. Enter the number of
the highest address with the keypad numbers and press 'Load' to confirm the setting. The Master Station will
then only poll around field units up to and including this address number. Note that the Master Station is a 32
channel unit and cannot have the highest address set above 32.
Press '3' to toggle between Baud Rate Doubling 'On' or 'Off'. Most systems will probably want to be run with
doubling on, as this improves the speed of communication on the loop by a factor of 2. However whilst
commissioning the system it may be better to start with this option set to 'Off'. It can always be change to 'On'
once the loop is successfully operating. Note that when upgrading from an older Pakscan II system baud rate
doubling will only operate successfully if all the field units are upgraded to Pakscan IIE.
Once these three parameters are set they will only become active when this screen is left by pressing 'MENU'.
This returns to the Top Setup screen shown in 8.5.1.
Baud Rate
R max
(ohms)
R max @ C max
(ohms)
C max
(uF)
RC Max
110
500
306
3.1
9.5 x 10
-4
300
500
306
1.1
3.6 x 10
-4
600
500
306
0.58
1.7 x 10
-4
1200
500
306
0.3
0.91 x 10
-4
2400
500
304
0.15
0.45 x 10
-4
Loop speed
110 to 2400 baud
Number of
FCU’s
in the range 1 to 32
Doubling
on or off
Setup:
