Delta Industrial Automation

Tips & Tricks



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!




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):


Exchange between Master PLC and Slave PLC:


Exchange between Master PLC and Slave temperature controller:


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.


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


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:


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):


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.


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


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


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


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


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:


  • NODE 20:



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!

Announcement: ISPSoft manual & v2.02 version

I know… just last week we announce the release of last version of ISPSoft, and today new version!
But the real reason of this post, is nto the new version, is the new Manual of ISPSoft!


Is already available on the website (Link)
And as always in our FTP (Link)

And just to keep you all updated, new ISPSoft 2.02 already available
On the website (Link)
And on the FTP “faster” (Link)
I add the announcement with the new stuff on the same software package.
You can found it in the PLC announcements folder (Link)
But the most important improvement in my opinion is the introduction of Wizards to help us to configure analog modules.

I hope you enjoy it!
And as always send your software feedback!

BTW, this is our 100th post!
Thank you so much for following us for all this time.
And I hope to celebrate with you all in our 200th post celebration

PLC Link (PLC to Temperature Controllers)

Happy new year 2013 for you all.
We decide to start this new ear with a new chapter of the PLC-Link series, I hope you like it!

As we see on the other chapters PLC to PLC and PLC to VFD, PLC Link is a method to easily communicate with Delta devices based on RS485 Modbus.
Because we already did it PLC and VFD, today we´ll do it with Temperature controllers.

1. Netwrok Structure:
Communication is RS485, so follow the twisted pairs recommendations when possible.

2. DTC Configuration:
First you have to setup the communication protocol as the PLC (9600,7,E,1 ASCII)
Second, remeber to change to 1 the parameter “Communication write-in selection”


3. PLC Software:
Step 1 -> Set up communication protocol
Step 2 -> Set the number of register to be read/write (Check manual to understand the D1436 and D1452 special register meaning).
Step 4 -> Select the registers to be read/write (H4700 = Present Value; H4701 = Set Value)
Check the following Table for DTA and DTB
For DTC or DTD jus follow the DTC manual table
Step 5 -> Enable PLC-Link

Do not hesitate to download the below examples
PLC LINK COM2 (PLC – DTC) and PLC LINK COM2 (PLC – DTA).dvp (Tested by DDC Automation)

Special Thanks to DDC Automation from UK for this example
Let us know your experience

PLC Link (PLC to VFD)

PLC-Link is not only a tool to exchange data between PLC’s.
With PLC-link you can also share memory space with a servo, inverter, temperature controller, etc…
In this case I would show you the procedure to do it with VFD-E series drive.

The advantage of this method agains the “sending frames one” is that you don’t need to program and trigger one frame for every value read or write to the slave.
With this method, you only have to configurate the communication, and you will have any Slave value in your master buffers.
follow the next steps:

1. Hardware
use exactly the same advices as the PLC-VFD communication post.

2. Decide the protocol to be used.
And write it on a post it in front of you. In this case we use protocol Modbus ASCII, 9600 baud,7,Even,1

3. Inverter configuration (almost same as PLC-VFD communcation post)
The important think on this step is get ready the inverter to receive orders from RS485 interface, so depending the inverter the values are going to be different. In this example I use VFD-E.
Check the parameters If you are going to use another inverter.

2.00 = 3
Source of First Master Frequency Command
3: RS-485 (RJ-45) communication

2.01 = 3
Source of First Operation Command
3: RS-485 (RJ-45) communication. Keypad STOP/RESET enabled.

9.00 = 2
Communication Address
in my example 2

9.01 = 1
Transmission Speed
3: Baud rate 9600bps

9.04 = 1
Communication Protocol
0: 7,E,1 (Modbus, ASCII)

4. PLC Software
In this case I recommend to have the manual opened, because basically is a matter to configure the PLC-Link special registers properly.

D1399:ID address of the first slave
D1434:Number of consecutive registers to be Read (by the master)
D1355:First register direction of the slave to be Read (H2102 = Frequency command)
D1450: Number of consecutive registers to be Write (by the master)
D1415: First register direction of the slave to be Write (H2001 = Frequency command)
D1480:Readed values Master Buffer (Slave 1)
D1496:Writed values Master Buffer (Slave 1)

To find what register I need to edit in each case, look in the manual for any of those registers, and look for the proper one.

And Check the following program and test it.

I’m pretty sure that system will save you a lot of time and efforts.

PLC-Link (PLC to PLC)

I have been a long time that I would like to post this post.

PLC-Link is a Delta protocol to share easily memory area between 2 PLC’s.
Basically, the big advantage of PLC-Link is to work with Delta PLC’s as Remote I/O units.

Furthermore, you can use Delta PLC as Remote I/O or any other Delta device (Servodrive, Inverter, etc..) because the protocol used to share the info is Modbus.
Today we’ll focus on how to communicate one PLC master with 2 PLC slaves.

Network Structure:

The communication will be Modbus RS485, so the wiring is so simple, two twisted pairs from connector to connector.

We decide to use 9600, 7, E, 1, ASCII, but you can use higher baudrate. In fact the new S2 PLC series (SS2, SX2, SA2, ES2 and EX2) can reach 921Kbps!!

Memory Mapping:
The plan is to share 6 registers from the slave 1 and put it inside the memory of the master.
And on the other way around too, put 6 registers of the master on the memory of the Slave one.

See below table

As you could see on the Slave software we transform the first three shared words to Slave Inputs and Outputs.
This is the proper way to read remotely the I/O of the slave into the master.


Program Master
Program Slave 1
Program Slave 2

Alternate mirror all together
name: den-eindhoven
Password: BuPd2175

Remember to enable PLC-link on network 5 to start to share.
And if some trouble occurs just try to reset the communication with the RESET_Com Symbol.


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