How to program valves with as-i?

Hi all,

I have a plc s7-300 cpu317 and i want to add some valves with as-i, but I don't know how to do it. I'am using an ifm c1411, I want to know how to redirect each valve (on/off), I mean what kind of blocs to use. Do you have a link with a tutorial?. Can you help me? Do you need more information about it?

Regards!!

Hello jryu;

As-I (Actuator Sensor-Interface bus) is a digital communication link that powers up and transmits on/off signals between an AS-I master and AS-I sensors or actuators (for example your valves). Newer profiles have been added in recent versions that support some analog signalling and Safety Integrated.

Much information, videos and training material can be found on the main AS-Interface website:

http://www.as-interface.net/?lang=en

Here is a basic document on AS-I from Siemens, which I will resume quickly in the next few lines:

• AS-Interface - Introduction and Basic Information

https://support.industry.siemens.com/cs/ww/en/view/1171856

As far as hardware is concerned, you would need:

- an As-I master, either a CP 343-2 (on the main rack of the CPU) or a DP-As-I link, a Profibus-DP slave to As-I master interface, for example;

- Asi cable, generally a flat, profiled 2-wire yellow cable designed for vampire-connection to AS-I slaves;

- an As-I power supply, producing 30 VDC; the As-I cable carries this power to the AS-I slaves  (24 VDC) and uses the extra 6 V DC as a carrier to modulate a digital signal, the As-I exchange data;

- an AS-I address programmer, if your slaves do not support auto-addressing by a master (not necessary if your slaves do);

- assorted As-I slaves (there are many types and forms of these); deepending on the As-I version selected, up to 31 or 62 slaves can be connected to a master.

This equipment (cable, power supply...) is all available from Siemens, but also from various other manufacturers on the market. For information please open the Products tab in the AS-interface.net link proposed earlier.

As-I buses run  for 100m, but this can be extended with repeaters or extenders, while the maximum number of slaves per bus is fixed limit.

Addressing of the slaves in the master is quite easy: the master reserves an area of 16 bytes for the slave data; the first nibble (4 bits, half of a byte) serves for diagnostics of the bus, the next 31 nibbles of data are associated to each slave on the bus as addressed. Extended addressing for 62 slaves is explained in the manual.

Here are a few more documents from Siemens on the CP 343-2 AS-i master, and some Applicatioon notes that propose functions to simplify crecoivering data from the slaves and diagnostic the bus:

• Manual CP 343-2 / CP 343-2 P AS-Interface Master (Edition 08/2008) with Supplements (Edition 08/2010)

https://support.industry.siemens.com/cs/ww/en/view/5581657

• Convenient Command Interface for central and distributed AS-I master for AS-Interface:

As-i interface library for S7 AS-i masters

https://support.industry.siemens.com/cs/ww/en/view/51678777

• Diagnostic Block and Visualization via HMI or webbrowser for AS-Interface

https://support.industry.siemens.com/cs/ww/en/view/50897766

Finally, to close the loop, here is an AS-I document from ifm Electronics, who manufacture your valves, so you can see how they fit in any AS-I bus, with Tips and Tricks for users of As-i..

AS-Interface manual - ifm

Hope this helps,

Daniel Chartier

Hi again!

I have ready the communication, I can open a valve with a command, I used a MOVE bloc with the next information:

w#16#100 |move| PQW256

With this I can open the valve, if I want to close it I use:

w#16#0 |move| PQW256

But the roblem is that if I add a new valve I dont know how to redirect the new output,

I can use this command to open and close the new valve, but I dont have the control of each valve because is the same output:

Open new valve:

w#16#2110 |move| PQW256

Close new valve:

w#16#0 |move| PQW256

I want to open and close the new valve but the output direction in my PLC is the same, How can I separate it?. can you bring me an example?, 

Thank you for the Information!!!

Hello jryu;

Sorry for the long reply, I misunderstood your requirements.

What type of valves are you controlling over As-i, digital (like solenoid valves, on/off) or analog (modulating positioner)? What make and model? Which As-I address did you attribute to the first valve, the one you control?

What does your configuration look like? I have opened the AC141x configuration over Step 7 manual, found on this ifm download page:

http://www.ifm.com/ifmus/web/pdownloads050_010_050.htm

Does your configuration resemble the attached screencapture? If so, you are accessing 4 words of analog output over AS-I.

By sending 16#w#100 to PQW 256, you are sending the binary message 0000 0001 0000 0000.

Then you send 16#w#0 to PQW256, so a binary signal pattern of              0000 0000 0000 0000.

So only bit 8 changes between the 2 messages.

I would like to know the As-I address to find out the relationship between this single bit change and the controlled valve, and see if there is an endian problem to be checked (checking whether there is a byte-swapping to be processed in your message)..

Next, what address are you using for the second valve?

Hope this helps,

Daniel Chartier

Hi dchartier!

1.- valves: SPX cu41-as-i extended H320 468

2.- As-i Address from the ifm for the first valve: 0x1A (I can control this one)

3.- As-i Address for the second valve: 0x2A

*I added a picture about my configurations on PLC and the IFM AC1411

With this configuration I use the commands to control the valves:

w#16#100 |move| PQW256

w#16#0 |move| PQW256

To the same output but without controlling each one.

I need to know what kind of commands I need to use to control each valve.

I hope you can help me correcting my errors in programming.

Best regards!!!

Hello jryu;

This is a shot in the dark, but here are 2 tests I propose you do.

1- keeping the same Profibus configuration as you show in your last post, try writing 16#w#200 to PQW256 to activate slave 2A.

2- (Is the configuration you implemented based on a sample project provided by ifm?) Try changing the configuration of the As-i master to digital addressing, as in slots 1 and 2  of the screenshot proposed earlier, and attached once more.

This will map slaves 1-31 to simple I/O addresses of the PLC which you can modify through a VAT table in Step 7 (and later in your program). Since the valves are solenoid on/off, this should be valid. Use the output address to command the valve (0 or 1 in the VAT table), use the input address to read the status (if the valve controller is equipped with feedback sensors)

First try to change slave 1 (through its I/O address as specified in your Step 7 configuration); if it opens/closes the first valve, do the same for slave 2.

If this does not work try open/close commands to slaves 8 and 9; this should work if the slave signals are swapped.

Tell us the results of the tests, please.

Hope this helps,

Daniel Chartier

its very simple and dosent have any special way.

just you should connect valve to asi module and asi module connect to asi master then it give an address that depend on the asi addres module 

so now you can use its address like all of other address like picture below