rotork Pakscan IIS, Техническое руководство

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64
Publication S130E Issue 1.0
Pakscan IIS Technical Manual
Method 1
Turn both potentiometers fully anti-clockwise. This sets the voltage to the maximum.
To set Port A's voltage. Disconnect the two wires from Port B and re-configure the loop. With the loop
running, turn Port A's potentiometer RV181 clockwise until the A LED on the door just goes out. Then turn
the potentiometer back slightly.
To set Port B's voltage. Reconnect the two wires at Port B, and disconnect the two wires at Port A. Re-
configure the loop. With the loop running, turn Port B's potentiometer RV182 clockwise until the B LED on
the door just goes out. Then turn the potentiometer back slightly.
Reconnect the two wires at Port A. Re-configure the loop and leave it running for a few minutes. Check that
communication with all field units is satisfactory.
Method 2
With the field units powered up the master station should be able to communicate to all of them once the loop
has been configured. If communications are not fully established see Section 10.3 for fault finding hints.
The line drive voltage can now be set with the aid of an oscilloscope. Allow the master station to configure the
loop and ensure all field units are in communication without any loopbacks.
Monitor across Port A loop wires and trim
V max down to V ideal by adjusting Port A's potentiometer RV181.
(See Fig. 13).
Remove Port A wires, allow reconfiguration to finish, again checking all field units are in communication with
only one unit in loopback (which should be the one that was connected directly to port A). Monitor across Port
B loop wires and trim
V max down to V ideal by adjusting Port B's potentiometer RV182. Remove the
oscilloscope and replace the field loop wires and reset the loop.
Fig. 13: Idealised Loop Waveform Monitored at the Master Station
V
max ........................................................................
V ideal ........................................................................
V
0 V
Master Station Request Field Unit Reply
V
max Adjustable by the potentiometers at the master station
V ideal The ideal voltage is 3 volts above V .
( Note that the actual waveform may be rounded due to the charging and discharging of line capacitance.)