SENEC H1/ Ethernet ?


Thread Starter

Tanweer Ahmed

Hi List,

Is there any difference between Siemens' SENEC H1 and Ethernet protocols?
H1 is Ethernet. I believe it is IEEE Ethernet, not DIX Ethernet. H1 is NOT TCP/IP. I believe it to be based upon a collection of ISO standards.

Horst Kolbert

Siemens' H1 was introduced in the early 80's and the name H1 was used for their Ethernet PLC, PC products and Ethernet network components. H1 products are based on IEEE 802.3 Ethernet on the physical layer and ISO 8073 on the transport layer. Meanwhile the brand name has changed to "Industrial Ethernet" and includes in addition to the ISO protocol (=H1) also full TCP/IP and UDP support. All implementations are based on Ethernet standards (=IEEE), ISO standards(=H1) or defacto standards (=TCP/IP).

Andrew Piereder

To expand on an earlier posting, H1 is a set of protocols that operates over ISO and TCP/IP, although MAP and Technology functions are confined to ISO. Send/Receive and S7 functions can function in either over top TCP/IP or ISO.
Whether ISO or TCP/IP, it still all Ethernet (IEEE 802.3).

If this is confusing, consider that Ethernet defines the electrical interface. Above this, another set of protocols handles the methodology for addressing and delivering actually messages. Over this exist the various H1 protocols which comprise a data structure. In many cases, the data structures are portable, such as S7 and Send/Receive are across ISO or TCP/IP.

D. C. Pittendrigh

Hi All

This one could get very dirty, I have a TCP/IP H1 interface module for an S7 300 in my office, I am currently testing the H1-IT module for the S7 400, I use it to talk to a SCADA system using the CP1413 driver, it is connected through my office Hub, and at the same time I talk to the same card via explorer and its IP address, to see HTML pages showing what goes on inside the PLC. This is of course still in testing, but the connections are working. Oh the card also can be set up to talk to the e-mail server on my office network, I will get there next week some time.

Donald Pittendrigh

Helmut Meissner

Hello Ahmed,

yes there are some differences:

- the yellow cable: double shielded coax cable, with special connectors
- connection to PLC, PC or workstation with special transceivers with AUI-Interface (15 pins)
- Protocoll-stack (named: TP4) is not TCP/IP

You needed special controllercard for the PC by Siemens (I think CP141), or boards by Schneider&Koch with TP4 protokoll-stack or DEC.

We used it to connect VAX- or HP-7000 Workstations and clusters to Siemens-PLC driven factories about 10 years ago.


Helmut MeissnerInc.

Andrew Piereder

Sinec or Simatic H1 (or as I believe it is now called--Industrial Ethernet) is a Siemens protocol or perhaps more accurately, a data
structure that sits overtop of Ethernet. H1 also has a variety of subprotocols, or feature sets that range from the straight forward send and receive to Siemens technology functions.

Andy Piereder
Pinnacle IDC
Hi Donald Pittendrigh,

I hope you have been successful in your experiment. I have situation where there are three H1 bus ( each H1 interfaced to several S-155u) in a steel plant which need to be linked to a Plant MIS system. Can you guide us on this?
Would request you to establish contact [email protected]

D. Pittendrigh

Hi All

I have in fact tested the use of the S7-400 H1-IT cards for mail server access but have not spent much more time on the HTML server side, as at this
stage (as per usual) I don't seem to find the time to deal with Java beans, the software package has been standing on my shelf gathering dust for over 1 year now.

All indications are that this will work most successfully however the client where this stuff is installed does not have a bridge from his control network to his mail server, and uses Intouch as a scada system so does not envisage deriving major benifit from the HTML server at this time, I will undoubtedly deal with this stuff sooner or later, who needs a Christmas
holiday any way.

I am looking at a similar problem to yours with a client who has 10 155U PLC's which he has networked over a star coupler, to a softPLC and Intouch SCADA. I met him yesterday and recommended an improvement in cycle time may
be acheived by using OPC server, I have to do some reading on the subject and will circulate my reply to you directly. Provisionally there should be no difficulty to do this but joining the 3 H1 busses to make one may not be a good idea due to the traffic which may already be on the bus system and required for control of the plant. I have worked in the steel industry and have seen what goes wrong when the timing on the roll stands goes out, I would not like to be responsible for your having these problems.

Donald Pittendrigh
We are now connecting our machines with H1. For the S7 side - easy. You can have either H1 or Iso on TCPIP. For our OPC software- with a SL4 driver - we use only H1. In the hardware manager the TCPIP function button has to clicked off. Our S7's for now include 30 machines. Plus 2 S5-135U. Here it wasn't so easy. After the 3 card, it works. We use the CP 1430TF (for H1). The Siemens CP1430TCP and a few "no names" didn't work. Remember Send ALL and Receive ALL in OB1!
Also important in both cases S7/S5 is the MAC address. We use 40.00.00.XX.YY.ZZ. The 40's area are free. XX is for the company(we are large), YY for the department and ZZ for the machine. This has to be changed in the PLC card. H1 and TCPIP networks can be mixed. However, every Network card has a MAC address, every card (PC,S5,S7) has to have a different Mac Address. One last thing, Mac (or H1) addresses are not routeable. Only TCPIP address. A machine from the internet can not have a connection through a - firewall.