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Modbus

MODBUS TCP communication between C2000 and AH500 in speed mode

Modbus RTU is a famous layer 2 fieldbus protocol used in wide range of applications since the mid 80’s and it has its encapsulation in a Ethernet frame, on TCP/IP protocol of layer 4 – 3 of OSI model. It can be used on Ethernet networks though a logic IP address, Modbus TCP uses the same function codes of RTU. The main advantage is that it is faster and can be used to send or receive data through any Ethernet device such as switches and routers in different topologies like star, tree or other line topologies using TCP/UDP/IP protocols in Layer 3-4. It can be installed in Standard 10, 100 or 1000 Mbit/s Ethernet technology based on copper cables, fiber optics or wireless standards can be used. Number of stations is almost infinite and it can go up to a speed of 1.5 Kbyte per telegram frame.

The full application note can be found here:

 

The ISPsoft program used is listed here:

AH500_MODBUS_TCP

 

 

 

 

 

 

 

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Easy control of Delta VFD drives

This week we would like to show you two new function blocks (FB) that we have developed to make even easier to use Delta Industrial Automation products.

Usually we need to control several AC drives from a single Master PLC and Modbus communication is a cheap and helpful way to get it.

In order to reduce programming and commissioning time we have developed two FB:

  • COM2_VFDLINK: Configures the communication parameters (baudrate, number of bits, parity,…) that all the nodes on the network have to share and informs about the communication state of each node.
  • DELTA_VFD: Controls each one of the slaves VFD, we can Start/Stop, Forward/Reverse, frequency command and reset faults. On the other side, the FB informs us about the status of the drive, alarm code, output frequency and output current.

Below you’ll find the FB library ready to be imported in your ISPSoft and a little pdf explaining the I/O of each FB, enjoy it!

VFDLink

VFDLINK FB

 

PLC LINK: 32 slaves and R/W 100words

Probably some of you already know the PLC Link feature of our DVP series PLCs, it allows us to easily exchange data between the master PLC and several slaves saving a lot of programming time.

Slaves can be PLC, drives, temperature controller and, in general, any equipment that includes and RS485 Modbus port.

For those who don’t know this feature here you can find other posts in this blog with detailed information:

 

Exchange between Master PLC and Slave drive (VFD):

https://deltautomation.wordpress.com/2011/08/05/plc-link-plc-to-vfd/

PLC-VFD

Exchange between Master PLC and Slave PLC:

https://deltautomation.wordpress.com/2011/07/21/plc-link-plc-to-plc/

PLC-PLC

Exchange between Master PLC and Slave temperature controller:

https://deltautomation.wordpress.com/2013/01/04/plc-link-plc-to-temperature-controllers/

PLC-DT

In general, the PLC Link feature is limited to:

  • 16 slaves.
  • Read up to 50 words (16 bits variable) from each slave.
  • Write up to 50 words (16 bits variable) to each slave.

Today I would like to show you how our PLC DVP12SE (Link) is able to overcome this limitations and increase the number of slaves and the number of data to be exchanged.

Using the DVP12SE PLC (fw versions 1.6 and above) you will be able to:

  • Communicate with up to 32 slaves.
  • Read up to 100 words (16 bits variable) from each slave.
  • Write up to 100 words (16 bits variable) to each slave.

 

Let’s take as an example an application where we want to communicate with first slave (ID1) and a second one over the 16 standard slaves, the 20th (ID20) for instance, at the end of this post you’ll find the example programs to be downloaded on the Master and in the two slaves.

 

First of all, we have to be sure that the communication parameters are the same on all the nodes connected to the Modbus (ASCII/RTU, baudrate, data bits, parity,stop bits) and also that all have a different node number.

MST-1

Two internal bits are very important in order to start the PLC Link functionality, M1350 and M1351:

MST-2

Also we have to indicate to our PLC that we want to access to more than 16 slaves and that we want to read/write more than 50 words on each slave:

MST-3

Next step is to assign to each slave (ID1 to ID32) his configured node number into the Modbus (in this case we have configured ID1 with node 1 and ID20 with node 20):

MST-4

In order to configure the PLC Link there’s no need to program complex polling structures nor keeping into account communication timeouts or errors in order to resend Modbus messages, you only need to fill a few special registers with the right values in order to indicate to the PLC which nodes you want to communicate and which registers of these slaves nodes you want to read/write.

In this example we will:

  • Master PLC reads D0~D49 (50 words) on PLC ID1 and stores the data on D100~D149 of his internal memory.

MST-5

  • Master PLC reads D0~D49 (50 words) on PLC ID20 and stores the data on D150~D199 of his internal memory.

    MST-6

  • Master PLC writes the values of his D200~D249 (50 words) on registers D100~D149 of the PLC ID1.

MST-7

  • Master PLC writes the values of his D200~D249 (50 words) on registers D100~D149 of the PLC ID20.

MST-8

  • Increments D200 and D249 (these values will be wrote on ID1 and ID20).

MST-9

On the slave’s side, we only have to configure the communication (ASCII/RTU, baudrate, data bits, parity, stop bits) and a different node number to each slave.

 

  • NODE 1:

SLV-1

  • NODE 20:

SLV-2

 

Here you have the programs of the Master PLC and both Slaves and also a pdf where you can find which registers you have to configure in order to read/write each one of the 32 Slaves.

PLC LINK 32 slaves

PLC Software

 

Now you have seen all the required steps to configure a powerful data exchange between a Master PLC and up to 32 Modbus slaves with just a few program code lines, enjoy it!

IFD9506 (part 3 of 3)

We arrive to the end of the IFD9506 monographic with the definitive application (and some final desert).
In this case we use the IFD9506 to add any Delta product to a Ethernet network.
In fact with the new firmware V1.07 is possible to add until 100 devices below the Ethernet gateway!!

And as a final climax, one last example of how to use IFD9506 as a gateway between one Ethernet HMI and some RS485 Delta periphericals (EX2, SV and DTB).

Have fun!

How to use IFD9506
Technical Announcement_DCISoft_V1_07

And put ethernet in our life ;)

IFD9506 (part 1 of 3)

Let’s play with Ethernet!

Industrial Ethernet has become the last 10 years as the replacement for the serial communication.  Not only because the speed, but for the simple compatibility with our main tools, the computers…

Each automation brand have their own protocol based on Ethernet (Profinet, Ethernet/IP, Ethernet Powerlink, etc…).
In Delta, we have been playing with Modbus from the beginning, so in the moment that we decide to enter to ethernet, the natural choice was Modbus TCP/IP.

But what happen with all the devices already in the factories working with Modbus RS232 or RS485 ?

To solve this need, we develop IFD9506.
This device is used to convert from Ethernet Modbus TCP/IP to serial communication Modbus.
And the following weeks we’ll share with you all several typical applications and functionalities of this device.

To start, we are going to use the simple communication HMI-PLC-DTB and we’re going to add two IFD9506 to achieve to communicate both three devices trough Ethernet as the picture shows.

To achieved, use the attached application tutorial.
HMI + IFD9506 + PLC.pdf
And take a look at the last page and our first approach to web server!

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