Specifications

50How to Create a New DP Master Project

using a FROM/TO instruction and extending the cycle time.

Automatic refresh is selected and cleared in the

PLC Settings

dialog. If either online update of

the CPU or offline update of the GID project have been selected, the automatic refresh option in

the Master Settings dialog is selected as well.

The data areas included in autorefresh and the respective device addresses can be set in

PLC

and GX IEC Developer (GID) Settings

. The settings in the CPU (stored in the IPARAM file) are

updated together with the download of the configuration to the PROFIBUS module (see

configuration download

and

online tool

) or via a GX IEC Developer (GID) project.

For details refer to the hardware manual of the Q series master module.

The automatic refresh option must be activated to enable the consistency function (see below).

Consistency (Q series master only)

The automatic refresh function (see above) must be activated to enable the consistency function.

Otherwise e.g. output data for a slave may be set in the slave in several segments and not in a

single PROFIBUS cycle.

The consistency function can be activated for System Q CPUs from OS version B (Sep. 2000).

The consistency function interlocks simultaneous access to the buffer memory by the CPU and

the DP master. This way, data consistency especially required for high-speed applications is

automatically ensured.

This interlock mechanism slightly decreases the transfer speed. Therefore, only enable the

consistency function, if you require data consistency.

For details refer to the hardware manual of the Q series master module.

Bus Parameters

To access the bus parameters from the graphical network editor, click on the

Bus. Param.

button

in the

Master Settings dialog

This function allows to select the baud rate and to modify any parameters like timeouts, which are

related to the baud rate. The settings are stored independently for each baud rate.

Relative timing factors are displayed as absolute times based on the selected baud rate. The

available parameters are: