To provide a backup control method in case of PLC failure, the client chose to add a set of additional manual controls wired directly to the drive control unit. This configuration can be kind of tricky; we effectively had two potential command sources to the drive. But we were in luck! Siemens drives come with the capability to switch between multiple Command Data Sets, control sources, which allowed us to quickly swap drive control from the PLC to control inputs mounted on the drive cabinet.

This tutorial walks through the process of creating a secondary CDS and integrating drive-specific IO to create backup drive controls using Siemens SCOUT programming software. The process is functionally identical using Siemens Starter; you can also use TIA Portal to configure your additional CDS, but the interface looks a little different. Nevertheless, you should be able to follow along with the specific parameters referenced in this blog – just know that the first couple of steps might look a little different in Portal!

Note: this tutorial assumes you’re starting with a functional PLC-controlled drive; if you aren’t there yet, these DMC blogs may be a good place to start! 

• Motion Control Solutions with Technology Objects in Siemens TIA Portal (Note: this is slightly outdated, and S120s can now be configured in Portal).

1. Our first step is to create a secondary CDS in drive configuration. In the “Configuration” section of the drive, click “Add CDS.” You can either add 
   a blank CDS and populate every relevant parameter yourself, or just copy over your primary CDS (which should contain data from your initial configuration and PLC). I’d recommend copying over the primary data; it’ll make our lives just a bit easier. So, all we need to do from here is tie in our manual inputs and clean up a couple of residual PLC-connected parameters.
   1. In the Scout’s drive Expert List, you can filter parameters to look only at those relevant to the Command Data Set(s). Now that we’ve added a secondary CDS, each of these parameters should be shown as an array, with indices for each CDS. For example, p840[0] represents OFF1 for CDS 0 (PLC controls), and p840[1] corresponds to OFF1 for our new CDS. 
   2. 
2. Now that we have a new CDS, let’s connect our inputs!
   1. Under the “Inputs/Outputs” section of the Control Unit project tree, we can see the digital IO for our drive. We have the option to tie parameters to either the incoming digital signal or to the inverse of that digital signal. This gives us a little bit of extra flexibility, which can come in handy if you need to get around some backwards wiring or switch between normally open and closed contacts. Depending on what hardware you’re using, your IO options might look a little different from the screenshots; if you find yourself short on IO channels, Siemens also offers a variety of terminal block modules that can provide additional IO (we use an analog module later in this example).
   2. 
   3. Local/Remote selector switch
      1. Now that we’ve added a secondary CDS, we need a way to tell the drive which CDS to watch for commands. We can tie our selector switch input to p810 (the Command Data Set Selection Bit): a 0 value will tell the drive to use CDS 0, while a high value (1) tells our drive to use CDS 1 (our secondary CDS).
      2. In this example, my local/remote selector switch is tied to DI 17. Notice that I’m actually using the inversion of the digital input. This is solely due to the way the switch hardware is wired: ‘local’ gave us a low value, so the selection bit would be backwards if we used the standard input. It’s a lot easier to play with software than re-label or re-wire the cabinet, so we’re just using the inverted DI!
   4. Fault acknowledge
      1. It’s always good practice to give yourself a way to acknowledge drive faults. If you have an optional screen insert (like this BOP) you already have an interface to acknowledge those faults. But, if not (or if your drive hardware will be secured in a cabinet and you can’t access the screen, like in this case), you can tie a DI to p2102 (Acknowledge All Faults). In our example, this parameter is tied to DI 2.
   5. Open/Close
      1. Since we’re commanding both forward and reverse motion, the open/close commands can get a bit tricky. We want either digital input signal to set the enable signal (p840), but we will also need to accommodate the difference between a forward and reverse command.
3. Open and Close inputs
   1. P840 is going to be our main enable, which we’ll set using the open/close inputs to the control unit. If you’re only trying to run your drive in a single direction (for example, if we only wanted to open our valve to release pressure, or if you wanted to lower an elevator to the ground), you could tie this parameter directly to a digital input wired to a “Run” button or switch; however, we want to be able to run our drive in both forward and reverse directions – meaning we’ll need to do a tiny bit of logic to set this enable if either the forward or reverse inputs go high.
   2. To do this, we’ll want to enable some smarter drive functions:
      1. Right click on the drive unit and go to “Properties.”
      2. Choose the “Function modules” tab and check the box to enable free functions. This will allow us to evaluate simple AND/OR statements within the drive.
      3. If you don’t have the option to enable free function modules, you might need to run through your drive’s DDS configuration again and make sure you checked the box labeled “extended setpoint channel” before following the steps above.
      4. 
      5. In the expert list, we now have additional parameters, starting at p20000.
   3. Now that we have additional parameters with which we can work, we need to tell the drive to actually process the bonus data. We configure this by setting p20000 to [9003] so it knows to evaluate our inputs.
   4. 
   5. From here, we’ll tie our open command to p20046(0) and our close input to p20046(1). The following parameter p20047 represents the “OR” evaluation of all inputs linked in p20046.
   6. From here, we’ll tie that parameter (p20047) to our OFF1 input p840[1], which will be our only conditional enable.
   7. 
   8. This sets our enable signal, but we also need to differentiate between our open and close inputs. Conveniently enough, Siemens has already given us the parameter we need – p1113, for setpoint inversion. We’ll connect our ‘Close’ input to p1113[1], which will tell the drive to invert direction while closing.
   9. 
4. We’ve now set our conditional enable signal from the open/close inputs, but we can’t forget that the drive is expecting to see a few other enables as well (OFF2 and OFF3). If we wanted to connect these to other inputs (for example, having a ‘Drive enable’ switch along with an ‘Open’ command), we could use the other enable parameters. In this case, however, we only have one option and will need to hard-code the other enables.
   1. We’ll set OFF2 and OFF3 both to 1, as pictured below:
   2. 
   3. One thing to note is that the drive should have different responses to a lost enable (coast-down, quick stops, etc.). If you’re looking for a particular response (i.e. you want your drive to STO if the operator releases your enable button), you should investigate each enable signal and make use of the one that fits your system best.
      At this point, we have a drive that should enable with our open and close switch! What we don’t have at this point, however, is a speed setpoint. We can either hard code a value (useful if you only want to run at a single speed, or don’t have a terminal board to supply an analog input signal) or tie an additional input to our setpoint value. In this example, we’re using a Terminal Board module (TB30) to add some analog input options to our drive IO, so we’ll take an extra step to set up an AI for speed setpoint.
5. To use our analog input for speed, we need to set up scaling for the input on the Terminal Board and tie our scaled signal to p1070[1], the main speed setpoint.
6. 

From here, we are all set – just make sure to download to the drive and copy RAM to ROM. After power cycling, we should be ready to utilize our new CDS and extra control options!

If you want to learn more about Siemens motion programming, take a look at these blogs:

• Siemens How To: Starter Executable Scripts and Custom Data Lists
• Simple Motion Control with an S7-1200 PLC and a Pulse Train Output (PTO)
• Go Further with Siemens Motion and Safety Using the S7-1517TF

The post How to Configure a Secondary CDS for a Siemens S120 appeared first on DMC, Inc..

A Sinema RC system is comprised of a single server (either a dedicated server PC or potentially a virtual machine) and at least one device (known as a ‘Client’) on the distributed network. DMC recently implemented a Sinema RC system to allow remote communication between an operator computer and a series of remote skids that were expected to regularly migrate across the continental United States.

Configuration

Sinema RC Server can easily be located behind a third-party internet router (for example, the one connecting your office computer to the internet), which is a fairly standard configuration. For this system, we used two Siemens M876-4 modems with Verizon SIM cards, in order to provide additional flexibility to the end user, who may be moving the server station to a new location. Using a separate router allows for movement of the system without any additional configuration of the system. Additionally, introducing a separate router meant there was no need to edit router settings or access the client’s internal network, which could be an important factor for end-users concerned with network or data security.

All SRC-enabled network devices in the system (in this case, the M876-4 modems) establish a VPN connection to the server, which effectively tricks each individual device into performing as if they’re connected, while maintaining the security of the network. Additionally, we configured a remote user connection, which will allow a maintenance technician to access the system remotely and provide any necessary support or maintenance. 

For this setup, you’ll need:

• An operator PC
• A wiped PC (without an operating system)
• Compatible remote devices (in this example, the remote M876-4)
  • Note that an additional Key Plug is required to allow a Scalance device to act as a Sinema RC client
  • Many Scalance switches are SRC-compatible, as long as the model is VPN-capable (models in the S, M and CP lines usually are)
• Reliable internet access for the server and any client devices

Basic Settings on the Server PC

Setup

1. Insert boot CD/USB into the appropriate slot on server PC
2. Start server PC, choose "Install/Update SINEMA Remote Connect Server". "Load from medium"
3. Follow instructions, using whatever settings fit your network configuration. For this example, we're using the following addresses:

Eth0 address – 192.168.20.250
Subnet – 255.255.255.0
Gateway IP – 192.168.20.12 (LAN IP of router)
External IP of the server:  166.169.147.13

Note: if you’re trying to use a SIM card for internet access, make sure you contact your service provider to confirm that your card is set with a static WAN IP address (most SIM cards default to a dynamic WAN IP, which changes upon every power cycle of the device)- ideally, the Sinema RC Server should have a static external IP address, which gives the Client devices a reliable address at which they can consistently find the Server. If you're configuring SIM access for your Client devices as well, they'll be perfectly happy with dynamic IPs and no additional configuration is necessary.

Bonus Note: there are a few detailed steps to setting up SIM cards with Scalance modems, and in DMC's experience this has caused a bit of a headache. Recently, Siemens has introduced a new offering in which they provide an M-876 devices with a Verizon or AT&T SIM card installed and activated; if you're looking for a quicker and easier implementation, make sure to reach out to your distributor for more information! 

Web-Based Management

1. Open an internet browser in the Operator PC and enter the Eth0 address of the server (in this case, 192.168.20.250). Note that the Operator PC must be addressed in the same subnet as the server.
2. Log in
   1. If this is your first time, use the default "admin"/"admin" login. You'll be prompted to change the username and password
   2. Otherwise, use the login credentials you configured at setup
3. Server Configuration
   1. Under the "Security" > "Network" tab, confirm that the "Activate Interface" checkbox is ticked, and that the port type is "WAN"
   2. Check the box labeled "Sinema RC is behind a NAT device", and enter the external IP of the router (in this example, 166.169.147.13)
   3. Confirm that the HTTPS port under "Web server settings" is set to 443, and Fallback port is 6220
   4. Save these settings

Groups
Create a communication group for Skid1.

1. Under Remote Connections –> Participant groups, click "Create" and name the group "Skid1"
2. Repeat, creating group "Service"
3. Define group communication
   1. Click the arrow button in the "Actions" column for the Service group
      

      

   2. Enable Skid1 and click "Save"
4. Within the settings for each group, we can define limits to regulate which groups can communicate with others. For example, we can adjust settings such that the ‘Service’ group can communicate with every other group, but we’ll restrict the ‘Skid 1’ group from communicating with anyone other than a member of the ‘Service’ group. This adds another layer of removal between our remote devices, which may be desirable for security purposes.

Configure Devices on the Server
For this example, we’ll create the device manually, but we could also create a .csv file (useful if you have a lot of devices to configure) and import them through the same page using the ‘Import’ button.

1. Create Devices: the M876-4 (Skid1)

2. Under Remote Connections –> Devices, click "Create" and name the M876 device. The basic Sinema RC package from Siemens allows for up to four (4) clients connected to the server, but extension options are available if needed.
3. Enable the option "Connected Local Subnets" and use the following settings
   1. Local LAN IP: 192.168.0.15
   2. Network mask: 255.255.255.0
4. Enable group "Skid1”
5. For later use: click the info button (

   

   ) and make note of the ‘Device ID’ and give the device a password. There is also a display of the device ‘Fingerprint’ – copy this down for later when we set up the remote device.

A Note on Server Router Settings 
At a minimum, Sinema RC requires TCP ports 443 and 5443 and UDP port 1194 enabled on the server internet gateway (in this case, the M876-4) to communicate between the server and client devices. If your server PC is located behind a managed router, such as most standard corporate internet routers, a network administrator may need to actively enable these ports for communication to your server.

Basic Settings for Each Individual Device

1. For standard setup, Siemens provides a built-in device wizard to help with the initial configuration of the device; follow these instructions by filling out as much information as possible. If you’re using a SIM card, the wizard should walk you through configuring your SIM provider and other information. One important point is that most major providers require advance registration of a SIM card with its corresponding device (via IMEI code). Please call your provider if this is relevant to you.
    
2. For a Siemens modem (in this case, the M876-4, but also the S600 series and others), a Sinema RC Key Plug is needed to allow Sinema RC connection. The purpose of the Key Plug is to store SRC-relevant data such as the WAN IP address of the router or user data. Once the Key Plug is inserted into the modem, additional settings are available.
    
3. If you didn’t enable Sinema RC using the device wizard (or if you’re taking a preconfigured Scalance device and updating for SRC access), navigate to “System” à “Sinema RC” and check the box to enable Sinema RC. Here, you’ll also point the device toward the WAN IP of your server PC (the WAN IP of your router), as well as the corresponding gateway (the LAN IP address of the modem).
   1. For verification, you can copy the ‘fingerprint’ of your server from the server PC over to your client. Paste in the fingerprint copied during server configuration and populate the ‘Device ID’ and password fields with the settings defined earlier.
       
4. Next, we’ll adjust our server settings to allow necessary communication to the server. Navigate to ‘Security’ → ‘Firewall’ → the ‘IPv4 tab’ and enable communication between all ports on the device.

5. We also need to create some additional settings in the IP Rules tab, to tell our modem to accept and allow all communication through its ports. You could minimize the scope of these rules for increased security, but that requires a defined list of all IP addresses communicating in the system (not possible for this scenario). For this example, we’re going to accept and send all packets from any IP address through our modem.

From here, you should be able to access the server from your remote device. With internet connection, your modem should automatically connect (unless you’ve configured additional restrictions). You can also run the Sinema RC client, assuming you’ve configured client login credentials, to test the connection from an operator computer.

When the server and clients are connected to the internet, they can be connected via secure VPN tunnels to allow any and all communication between configured devices, including remote access by an operator with Sinema RC Client software installed on his or her PC. 

Learn more about DMC's partnership with Siemens.

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