FAQ: Siemens S7 Plus Driver

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Introduction

The following is a list of S7 plus frequently asked questions has been compiled to help you better understand functionality and restrictions associated with this WinCC Open Architecture communications driver for the new line of Siemens S7 controllers.

Which type of controller and simulation can I work with?

S7-1200, S7-1500, ET200SP, S7-1500 Software Controller, PLCSIM, PLCSIM Advanced.

Is there a performance difference compared to the old S7 driver?

The S7 Plus driver uses symbolic addressing only. On the same machine, we observed a performance increase of about factor 5-10 compared to S7 driver TIA Symbolic (in WinCC OA 3.14).

What is the S7 driver licensing model look like?

The underlying S7DOS layer counts total connections to unique IP addresses (of PLC Communication Processors CPs). The pool of licensed connections is shared with every SIMATIC software on the same computer. Therefore online-connections from TIA Portal or any WinCC at the same time will reduce the remaining licenses for WinCC OA and vice versa. See attached a small table to calculate the licenses for your needs. We have also added H-PLC as well as we know they are currently not available.

Licensed
Connections
(Per WinCC OA Server)
Single PLC Redu LAN or H-PLCRedu LAN and H-PLC
8842
64643216
512512256128

What do I need the SIMATIC SCADA Export Plugin for?

As the S7 Plus driver uses symbolic addressing, access to the engineering data of the connected S7 PLC is required. These data are provided by the TIA Portal Export Plugin, which integrates into TIA Portal V13 SP1 or V14 via project or PLC station context menu.

How many connections do I need to one Siemens S7-1500 PLC?

Only one single connection on the S7DOS layer is established per S7 PLC.

Does redundant LAN work? How many connections do I need to connect to a S7-1500 with redundant LAN?

Yes, the S7 Plus driver also supports redundant LAN. As a consequence two connections on the S7DOS layer are established per S7 PLC.

Are H-Systems supported and how many connections do I need for them?

Not at this current time for the supported controller types.

Does the S7 Plus driver support alarming?

No, alarming support is on our agenda for the next release, version 3.17.

Can I connect to S7-300/400 using the S7 Plus driver?

No, only controllers from the S7+ series like S7-1200 and S7-1500 can be connected.

Does the S7 Plus driver run on Linux?

Yes, the S7 Plus driver is available for all delivered WinCC OA platforms.

Can I use optimized Datablocks in my TIA Portal project?

Yes, optimized Datablocks (Instance-DB or Global-DB) can be used.

Can I use User-Defined Types and Arrays in my TIA Portal project?

Yes, User-Defined Types and Arrays can be used separately and combined for Datablock variables and Tags.

Is my TIA Portal engineering know-how somehow protected? Can I use protection levels on the S7 PLC?

Engineering firm or end-user Intellectual property is protected in two ways:

  1. The TIA Portal Export Plugin exports the engineering data in a securely protected way producing an encrypted export file. Additionally, the export file contains only relevant information for SCADA or HMI applications and not, for instance, the complete function block source code.
  2. The S7 Plus driver is able to communicate with protected S7 PLCs, i.e. having an activated protection level. The necessary password for accessing a protected S7 PLC is stored safe and encrypted in WinCC OA.

Why do I need the S7DOS component?

S7DOS is the common communication layer for all Siemens Software Products connecting S7 PLC. Therefore also the S7 Plus driver shares this functionality.

Can I use own S7DOS Access Points instead of “S7ONLINE”?

Yes, you can define own Access Points by opening the “Set PG/PC Interface” from S7 Plus Connection Panel or Windows Control Panel.

Can I upgrade from using classic S7 driver to S7 Plus driver?

S7 connections using “TIA Symbolic” can be merged to the new S7 Plus driver by using the “S7+ Migration” Panel from System Management. All other types of S7 connections have to be upgraded manually.

Can I use my S7 driver license to run the S7 Plus driver?

No, because the S7 Plus driver uses another license keyword [s7plus]. Nevertheless, there are up to 8 connections possible even in case of an invalidated license.

Can I use TSPP with the S7 Plus driver?

No, TSPP cannot be used. Instead, subscriptions can be used.

What is the difference between pollgroups and subscriptions?

Using pollgroups the S7 PLC is periodically requested to send a set of associated variable values. The subscription functionality allows the S7 Plus driver to subscribe for variable values on the PLC side once (i.e. “configuration”) and have the values sent automatically by the S7 PLC either periodically or on change of some subscribed variable value without the need of actively requesting any variable value. However, the amount of subscriptions and subscribed values is limited by the S7 PLC.

What does the log entry “Active connection for XY (condition [1-4]) switches from A to -1” mean?

This log entry indicates a change of the currently active connection named XY from previous state A (possible values -1,0,1) to new state -1. Connection -1 means no active connection at all.

What does the log entry “The integrity of the project is broken” mean?

In general, this log entry means that something between the “offline” configuration (i.e. TIA Portal Export file and internal DP configuration) and the online connected PLC is inconsistent. The error might, for example, mean that PLC type is set to “S7-1200” but the IP address points to some S7-1500.

Why can I connect to a S7 PLC although the PLC type is invalid?

This only happens when there already was some valid connection established for the PLC type in question since driver startup. This behavior is due to some internal details of the used communication library.

Why is there a poll group inside of a subscription?

The poll group inside of the subscription is a backup if the datapoint has not changed in the amount of time that is set in that poll group.

Notes:

Through this mechanism it is possible to receive unsolicited data from the PLC which means that actively polling data is not necessary. Each subscription is linked to a poll group in a 1:1 relationship.

A poll group must not be used for polling and as subscription at the same time. For example, the poll group PG1 is used for an address with receive mode “Subscriptions”, you must not use this poll group for an address with receive mode “Polling”.

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