TSAPs (transport service access points) are access points for ISO transport connections and ISO-on-TCP connections that are required for establishing connections. If two communication partners such as an S7-300 (device A) and an S7-400 (device B) exchange data via an ISO-on-TCP connection, the configuration of the TSAPs in devices A and B must match. The values for the local and remote TSAP must match in pairs.
Fig. 01: Configuration overview
The local TSAP "ISO-A" is configured for device A. The local TSAP "ISO-B" is configured for device B. Consequently, in device A the local TSAP "ISO-B" of device B is configured as a remote TSAP (see Fig.01). In device B, the local TSAP "ISO-A" of device B is configured as a remote TSAP.
Fig. 02: Properties dialog of the ISO-on-TCP connection in the S7-300
Special features of TSAP configuration:
TSAPs of length 2 are a special feature. An example of this is the TSAP 0x0102. From here onwards, the TSAPs are now to be viewed in hex format. TSAPs of length 2 are reserved in the S7 system for other types of communication. The table below provides an overview of the individual types of communication:
|0x0100 - 0x01**
||Programming device connections or diagnostic connections from STEP 7|
|0x0200 - 0x0F**
Various communication mechanisms in the S7 system
|0x1000 - 0xDF**
||These TSAPs are reserved for configured S7 connections.|
For the S5 compatible communication via ISO-on-TCP connections and ISO transport connections, TSAPs with a length of 2 bytes cannot be used.
If a TSAP of length 2 is used for the S5 compatible communication via ISO-on-TCP connections or ISO transport connections, the connection setup for the firmware of the Industrial Ethernet CP cannot be correctly assigned because the TSAP could match both a communication connection of S5 compatible communication and a communication type mentioned above (see tables).
Fig. 03: Configuring the TSAPs 0x0102 with length 2
When configuring a local TSAP of length 2, the following message is automatically issued by STEP 7.
Fig. 04: Message in STEP 7
- Using TSAPs 0xE0... and 0xE1...:
All TSAPs that begin with 0xE0 or 0xE1 are also reserved in the S7 system. These TSAPs can also be longer than 2 bytes.
|First TSAP byte
||TSAP for open communication via Industrial Ethernet. The user must define the TSAPs in the connection specification in the CPU program.|
||TSAPs for the PROFINET CBA communication type. The TSAPs are managed by the system itself and cannot be defined by the user.|
The CPUs with integrated Industrial Ethernet interface support the open communication via Industrial Ethernet using ISO-on-TCP protocol. 0xE0 is always used in the first byte of the local TSAP.
Fig. 05: Configuration overview
Data is exchanged between an S7-300 with Industrial Ethernet CP (device A) and an S7-400 with integrated Industrial Ethernet interface (device B). In device B, the local TSAP "E0.49.53.4F.2D.42" is configured for open communication via Industrial Ethernet. In device A, the local TSAP of device B is configured as a remote TSAP.
Fig. 06: Properties dialog of the ISO-on-TCP connection in the S7-300
In the S7-300 and S7-400 no local TSAP may be configured for the S5 compatible communication via ISO-on-TCP connections and ISO transport connections that uses 0xE0 or 0x01 (see Fig.) in the first byte.
Fig. 07: Configuring a local TSAP 0xE0
The user is not informed of the configuration of a TSAP with 0xE0 or 0xE1 in the first byte by a message.