User`s manual

GFK-2334A Chapter 3 PROFIBUS Master CPU Configuration 3-9

Parameters Tab of the Master Properties Dialog Box

Scan Cycle Times

Typical

This field displays the estimated time (µs) required for one scan of the PROFIBUS network. This is a

read-only field.

Minimum

The minimum I/O scan time in 100 microsecond increments. This may be required if the I/O

modules are restricted in how often they can be scanned. To use this parameter, click the Minimum

check-box to activate it. Then enter the value in the field next to it. The value you enter here

represents the number of 100 microsecond increments. For example, in the figure above, the value

is 2 x 100 = 200 microseconds.

Range is 2 to 65535.

Scan Cycle

Times

Parameter

Group

These parameters allow you to set minimum and maximum scan cycle times for the Watchdog

timer.

Auto

The maximum I/O scan time and Watchdog timer are assigned automatically based on the number

of slave devices configured.

Maximum

The maximum I/O scan time in 10 millisecond increments. If the scan time exceeds this value, the

PROFIBUS master faults all the slaves, reinitializes them, and brings them back online. When the

maximum I/O scan time is updated, the Watchdog timer is also updated.

Range is 12 to 65535.

Watchdog

If a PROFIBUS slave does not receive any communication from its master within the Watchdog

time, the slave generates a fault, the outputs are set to 0, and the slave is reinitialized by the

PROFIBUS master card. Assigning a value affects the maximum cycle time.

Options Parameter Group

Repeater

Select this check box if there are repeaters on the network.

FMS Devices

Select this check box if there are PROFIBUS FMS (FieldBus Message Specification) devices on the

network.

Stay Offline on

Error

Select this check box if you want the PROFIBUS master to stay offline when the Token Error Limit

or response Error Limit is exceeded within 256 token cycles.