FC310x - Profibus PCI fieldbus card


The difference between PROFIBUS MC and PROFIBUS DP is that the PROFIBUS cycle is constant, with a jitter of a few microseconds (for PROFIBUS DP, the jitter is greater than 100 µs), and at the start of the cycle a broadcast global control telegram is sent, which can be used by the MC slaves for synchronization. This enables precise synchronization of drive control loops with the NC.

However, this precise synchronization means that bus disturbances, switching off of slaves, pulling of bus plugs etc. will usually lead to a loss of synchronicity between master and slave, since the bus timing is changed.


FC310x with Simodrive 611U has Plug&Play functionality

The following steps are required for operating a Simodrive 611U on a FC310x:

Set FC310x to operation mode "DP/MC (equidistant)".
Append box "Siemens AG, Profidrive MC".
Adjust 611U station address ("PROFIBUS" box tab).
Append axis (or 2 axes for 611U with 2 axes) to NC task, select axis type "continuous axis".
Link axis (or axes) with 611U (select axis type "ProfiDrive MC" in the "Settings" axis tab, then link with 611U; for a 2-axis 611U, both axes have to be linked, otherwise a 611U error will occur).
Press the "Calculate Equi-Times" button on the "FC310x" tab at the FC310x.
Save project in the registry and start TwinCAT. The 611U should now change to RUN, the axis can be operated via the NC online menu.

Should this not be the case, check the following:

DpState of the 611U in TwinCAT is 2: Check 611U station address.
DpState of the 611U in TwinCAT is 5: Check whether the correct PROFIBUS module is inserted at the 611U.
DpState of the 611U in TwinCAT is 7: Check whether P922 is set to the correct standard telegram (according to the ProcessData tab for 611U in the System Manager).
DpState of the 611U in TwinCAT is 0, but 611U still does not change to RUN: Check the 611U firmware version; for firmware versions below 3.4.3, 611U synchronization errors (error 597 or 598) can only be rectified via a hardware reset of the 611Us, otherwise look up the error code in the Siemens manual.

If several 611Us are configured, the equidistant times may have to be adjusted (see below).


DP/MC Equidistant Mode

In order to operate the FC310x with PROFIBUS MC, the Operation Mode "DP/MC (equidistant)" must be set on the tab "FC310x" (for TwinCAT 2.8 or TwinCAT 2.9) of the master. Whichever task uses the equidistant functionality of the FC310x (usually the NC task) should have the highest priority, as otherwise the synchronicity can be disturbed. Additionally, the Sync Mode can be selected. This specifies where the synchronization signal is generated.


Disabled (PC is Sync Master)

The synchronization signal is generated by the PC, the FC310x synchronizes itself with the PC (PROFIBUS cycle jitter approx. 2-4 µs).

PC is Sync Master

The NC Access Time specifies by how much the PROFIBUS cycle is shifted towards the TwinCAT cycle, the PLL Sync Time should be set to approx. 10% of the NC-Access-Time (max. 50 µs).


Sync Slave

The synchronization signal comes from another device, whose Sync mode must be set to "Sync Master". The connection between the sync master and the sync slave is made through a hardware link. This is only supported as from FC310x hardware version 4 and firmware version 3.00. No times have to be set.


Sync Master

The synchronization signal is generated by the FC310x, the PC synchronizes itself with the FC310x (jitter of the PROFIBUS cycle approx. 1 µs).

FC310x is Sync Master

The NC Access Time specifies by how much the TwinCAT cycle is shifted towards the PROFIBUS cycle.


Setting of Equidistant Times

The Calculate Equi-Times button (TwinCAT 2.8: see FC310x tab, TwinCAT 2.9: see MC tab) can be used to automatically set all equidistant parameters. The only parameter that may possibly have to be adjusted later is the NC Access Time, because this depends on the maximum TwinCAT jitter and on the maximum mapping time. This in turn depends on all the devices, so that adding and linking boxes to other devices has the effect that it may nevertheless be necessary to change the NC Access Time for an unchanged device. If "I/O not at task start" is selected (see the Synchronization chapter), then the NC Access Time also depends on the task runtime. To avoid having to manually adjust the NC Access Time every time the Calculate Equi-Times button is pressed, the ratio of NC Access Time to Cycle Time can be specified (set to 15% in delivery state).


Disabled (PC is Sync Master) or Sync Master

The NC Access Time must be greater than the maximum TwinCAT jitter plus the maximum mapping time, plus, if "I/O not at task start" is selected for whichever task linked to the FC310x has the highest priority, it's task runtime.


Diagnostics of Equidistant Times

The EquiDiag tab (TwinCAT 2.8) or MC-Diag tab (TwinCAT 2.9) in the System Manager can be used for diagnosing the equidistance times, or this can be done via ADS in the control program (see chapter Master diagnostics).