Baumer GK473 User Manual

Page 10

Manual_GK473_Profibus_EN.doc 10/16

Baumer IVO GmbH & Co. KG

04.05.11

Villingen-Schwenningen,

Germany

5.3. Transparent gateway function

5.3.1. General information

Basically all commands with code „A“ ... „z“ are transparently transmitted by Profibus to the SPAs and
vice-versa, allowing addressing each SPA individually or altogether by PLC broadcast command. The
gateway does not check whether an SPA is connected by the registered address, neither the code of
the command.

The gateway will only accept commands with code „@“ for local processing without SPA commitment,
the response is transmitted immediately to the Profibus master by Profibus.
Basically the gateway is responding to every command received from DP-Master (PLC).
The DP-Master always has to wait for the response prior to sending another command to the gateway.
This enables the DP Master to always recognise when a command is successfully accomplished.
The response will be

• by passing transparently the SPA response if an individual SPA was addressed and is duly

replying.

• by error signal if the SPA does not reply after having elapsed the timeout (approx. 100 ms)
• by confirmatory response after having transmitted a broadcast command (to address 99,

83h) to all SPAs.

Any timeout in the DP master for monitoring the gateway replies should not be less than 400 ms.

5.3.2. Broadcast commands

Due to the bus conflict, SPAs are generally not in a position to reply via RS485 interface to broadcast
commands, i.e. to commands addressed to all SPAs at the same time (address 99, 83h). Therefore, on
behalf of the SPA the gateway will transmit a response to the DP master in the format described
below. The response is only repeating broadcast address (99) and command code. It is only to confirm
that the broadcast command was transmitted by RS485 interface to all SPA. It is NOT confirming any
acceptance or accomplishment at the end of the SPA.

Example: Broadcast command „i“ is programming all SPA to „mm“ as measuring unit.

Zhl Adr Cmd

data

transmit

83h 69h 30h 00h

00h

00h 00h 00h 00h

00h

Zhl Adr Cmd

data

response

83h 69h 00h 00h

00h

00h 00h 00h 00h

00h

5.3.3. Interface documentation

The respective SPA’s interface description(s) is giving complete information on the SPA interface. The

interface description is indispensable for editing a gateway application.

5.4. Automatic gateway functions

5.4.1. Automatic SPA recognition

After switch on the gateway will automatically scan all SPA addresses. Each address found is stored in the internal memory.

Later, the addresses of all SPAs connected may be compiled by special command for read-in by Profibus.

This function takes for granted that all SPA are already “ON” or at least being switched on together
with the gateway. A reliable information on all SPA connected is available at the beginning of the
Profibus communication.