3
2TLC172007M0203_B.doc
Problems due to communication and downloading of programs in the network
·
If the Pluto units in the “Bus Status” window is flashing red/green and showing the fault code Er18
and some other fault codes (among others Er24, Er27 and Er60) it is probable that the bus cable is
not correctly connected/installed or that a Pluto unit is causing disturbances on the bus.
·
Start by disconnecting the upper left connection block at all Pluto units (put a screwdriver in the slot
on the contact block and lift the block upwards). For each and every of the units, switch off and on
the voltage and download the program again without connecting the Pluto to the bus. Check that the
correct station number is shown on all units.
N.B.!
Make no changes in the program and no
compilations in this stage. All units must be loaded with exactly the same project.
·
Check the connections of the bus cable to the Pluto units. All CH shall be connected to each other
and all CL shall be connected to each other. The ends of the cable shall be equipped with
termination resistors of 120
Ω
each.
·
If the length of the bus cable is not possible to read/estimate it is possible to measure the bus cable
with a multimeter. Create a short circuit at one end of the bus cable and measure the resistance
between the two conductors for CH and CL without a termination resistor in the other end. When
performing the measurement all Pluto’s must be powered off and the terminal block for the bus
connection shall be disconnected.
Total resistance = resistivity * total cable length * 2/ cable area
For copper with the area 0,5 mm
2
the resistivity is 0,0172 mm
2
/m.
Example:
With a total resistance of 10,3
Ω
the cable length will be approximately 150m.
·
Now reconnect one Pluto at a time and check in the “Bus Status” window that the units are shown
and are OK. The fault code Er18 can be shown; try to reset by pressing the button “K” at the Pluto or
make a “Reset all Pluto’s” to get started again. If this doesn’t help; replace the last Pluto that was
connected with another unit, which must have the program downloaded before being connected.
·
All Pluto units in a project are loaded with the same program. The IDFIX number determines which
part of the project that is being executed for the particular Pluto. This can be a help for
troubleshooting: Pluto units can be changed around to see if the fault follows a particular Pluto or
not.
10,3*0,5
0,0172*2
=149,7
