TRAMAS DIRECTAS A UN PLC

Hola amigos,
estoy trabajando con un plc de matsushita Nais, mi problema es que intento enviar tramas directas al plc por puerto serie, mediante VISA, y no consigo respuesta del plc, al enviar datos no me da ningun tipo de error, os pongo mi VI, la trama que le envio es para leer el estado de una entrada.
Ya antes he controlado otros aparatos desde labview con envio de tramas, estoy un poco estancado
Un saludo y gracias
Solved!
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Attachments:
COM_NAIS.vi ‏60 KB

El opc de nais lo tengo, con el opc si que me funciona, me lee en todas las areas de memoria y escribe en las internas, no se os ocurre algo por lo que no me funcione el envio de tramas de la manera que yo lo hago. La finalidad de que lo quiera utilizar es que es mucho mas rápido el envio directo de las tramas, la trama a enviar es % 01 # RC S X 0000 1D CR
muchas gracias

Similar Messages

Logging data after a trigger with Lookout Direct

Hi,
I would like to log data with Lookout Direct after a trigger input (not periodically or continuously). I am using Lookout DIrect version 4.5.1 build 19 and a Direct Logic 250 PLC.
Does anyone have suggestions on how to do this? I would prefer that this data be logged into Excel. I have 24 sensors connected to the PLC and each time a sensor transitions from hi to low I would like to log the time of transition.
Currently I have individual spreadsheet storage objects for each sensor as well as individual latchgates to indicate when logging has been completed. In the PLC code there is a state machine for each individual sensor as well and one of the states waits for an acknowledgement from Lookout that data logging has been completed before moving on to the next state (I will have to dig a bit deeper to remember exactly why I needed to do that).
I am hoping there is a more traditional approach that is easier than what I am doing. One of the problems I have been facing is Lookout Direct crashing every few days and I suspect it is because the sensors are often sensed within milliseconds of each other and opening/closing so many files is causing problems. I worked through a list of possible reasons that Lookout may be crashing (provided by tech support) and I am nearly convinced I am just asking too much of the program...
Any help will be greatly appreciated
Thank you,
David

In case someone can help with this, here is a bit more information about my application and the PLC/Lookout code I have developed:
Actuators have two positions, nominal and folded. Prox sensors are used to monitor the position of actuators. 12 actuators can be monitored simultaneously. The time at which prox sensors are sensed high is recorded so that actuator speed and actuation success is logged.
The PLC code consists of 12 separate state machines, each with the following 8 states:
State 1
System reset or nominal timer reset
Wait for nominal prox release
State 2
Nominal prox released
Wait for folded prox sense
State 3
Folded prox sensed
Wait for folded ack from Lookout (acknowledges that timer value has been logged)
State 4
Folded ack from Lookout received
Wait for folded timer reset (this state is active for one scan only)
State 5
Fold-in timer reset
Wait for folded prox release
State 6
Folded prox released
Wait for nominal prox sense
State 7
Nominal prox sensed
Wait for nominal ack from Lookout (acknowledges that timer value has been logged)
State 8
Nominal ack received from Lookout
Wait for nominal timer reset (this state is active for one scan only)
Lookout acknowledges that timer values have been read and saved with LatchGates. Lookout uses a SpreadSheet Storage Object to save the PLC timers when the PLC enters states 3 or 7 (prox sensor triggered). The logged member of the SpreadSheet Storage Object is used to change the state of the LatchGates which, in turn, signal the PLC to proceed to the next state. When the folded file is saved, the nominal LatchGate is turned off and the folded LatchGate is turned on and vice-versa for the nominal file.
The LatchGate/SpreadSheet Storage combination is what I am hoping to improve upon. I believe Lookout is crashing when 12 SpreadSheet Storage Objects log to 12 different files during the same 1 second period of time.
If anyone has suggestions of a way to log this data in the PLC memory or a software package better suited for this application, please let me know! I believe this would be simple with LabVIEW, unfortunately obtaining the additional hardware and software that I would need hasn't been easy!

PLC is better than PXI?

I have a question in my mind.
What are the limitation of PXI over PLC and What are the advantages of PXI over PLC?
Please leave your comments.

Hi KRAZE4LV,
Comparing PLCs to PXIs can somewhat seem like comparing apples to oranges. While they both have specific uses, along with advantages and disadvantages, I would first steer those interested in this to a brief overview of PXI Systems. We have had customers make the move from PLCs to PXIs, and one case study in general comes to mind. I might consider a cRIO in many cases to be a more direct replacement for PLCs, and there has been a few discussions on this issue. The main constraint of a PLC system is that PLCs are not generally used in harsher environments, and is significantly less rugged than our other systems. Feel free to add your own input though.
Best,
Jason M.
Applications Engineer
National Instruments

Process Failure when communicating over MODBUS using LabVIEW 2011 and DSC

I'm currently trying to read from a PLC's holding registers using MODBUS/TCP. I've confirmed that the PLC is updating the values and responding to MODBUS communication correctly using a third party program called Modbus Poll. However, when I try to poll the PLC using LabVIEW's shared variable engine, I am unable to read any values from the same addresses that I'm viewing with Modbus Poll.
My setup simply consists of a PC connected directly to the PLC over Ethernet, with no router in between. I am using LabVIEW 2011 SP1 with the DSC module.
I opened the NI Distributed Systems Manager to view the status of all shared variables in the Modbus library that I created and I've noticed that the CommFail bit is permanently set to "true". All other variables with a "read" access mode report "Process Failure". I've tried restarting the process as well as stopping and starting the local variable engine with no success. I've also restarted my computer several times to see if any services were failing, but this does not seem to have fixed the problem.
I finally resorted to monitoring communications over the network card that I have the PLC plugged into via Ethernet using Wireshark and I've found that while Modbus Poll is communicating with the PLC, many MODBUS and TCP packets are sent and received. However, when solely using LabVIEW or the NI DSM to communicate with the PLC, there does not appear to be any communication over the network card.
Something that may be worth noting is that I was able to communicate with the PLC and read values from it with the DSM on just one occasion, when I first figured out which addresses I should be reading from. It all stopped working shortly thereafter. Prior to this, "CommFail" was not usually set to "true" with my current configuration. Thinking that it was my firewall, I have since turned my firewall off, but this seems to have had no effect on the problem either.
Any help on this matter would be appreciated.
Solved!
Go to Solution.

Just a thought but I think the register addresses used by LabVIEW are one off of the actual register #. I was using a CRIO as a modbus IO Server and had to shift the register addresses by 1 to get things to work correctly (can;t recall if it was +1 or -1). This is documented somewhere on ni.com but can;t seem to find it now. But here is another link that may help:
http://zone.ni.com/reference/en-XX/help/371618E-01/lvmve/dsc_modbus_using/
Dan

LabView and AB Ethernet/ip

Has anyone used LabView to communicate or collect data from a ethernet/ip device (AB or other)? I am considering collecting cycle time statistics from several plc controlled machines via ethernet to a server running LabView. Any advise or examples would be helpful.
Thanks

"SysApp" wrote in message
news:[email protected]..
> Has anyone used LabView to communicate or collect data from a
> ethernet/ip device (AB or other)? I am considering collecting cycle
> time statistics from several plc controlled machines via ethernet to a
> server running LabView. Any advise or examples would be helpful.
>
> Thanks
I am currently using LabView 6.1 with the Datalogging and Supervisory
control module (add on) to send and receive data to an AB SLC 5/05 PLC. The
SLC 5/05 is equipped with ethernet and with an OPC server such as RSLinx
(for AB products) you can communicate directly to the PLC. You don't need
the Datalogging and Supervisory Control module, there is the datasocket
connection buil
t into LabView already. You just need the OPC server (RSLinx
for AB) to relay the data.
Regards,
Surcher

New Labview Resource

REAL Controls, Inc., a National Instruments Alliance member, has just
published our new website. We have provided a number of VI's for free
download and personal use. These include a couple of cool keypads,
communication drivers for Johnson Controls Companion process controllers and
for Automation Directs brand of PLC's. Stop by to check us out at
http://www.realcontrols.com.
Sent via Deja.com http://www.deja.com/
Before you buy.

It's not correct to say that just dropping a resource control itself on the front panel or diagram opens a session. The resource is automatically opened when calling VISA function (i.e. a write or a read), if the resource was not explicitly opened with the VISA Open function. You can see this yourself. Put just a resource control on the block diagram, select the resource and run the VI. Click the arrow on the control and look at the resources. Now, wire a VISA Write to the control, run the VI, and look at the resources. You will now see a little icon next to the resource you selected. This indicates that the resource is open. The automatic opening of a resource was a change made to VISA several years ago and you will still see the VISA Open in instrument drivers. It's not a bad idea to always use the VISA Open function. For serial, you would put it before the VISA Configure Serial Port.
Attachments:
Open Resource.PNG ‏4 KB

Tag engine to opc server communication protocol

When the tag engine talks direct to a plc with modbus rtu, there is a CRC checksum built into the communication protocol to provide reliable data transfer. When the tag engine talks directly to an opc server program, what protocol is used?? Is there any kind of checksum to verify data integrity??

OPC Client to OPC Server communication protocol is based on Microsofts DCOM architecture, which is an object model oriented communication mechanism based on RPC (TCP/IP). I as know, there is no checksum verification specifically as known in PLC protocols. However, there are some mechanism to support fault tolerance better. (see DCOM Technical Overview, section, Fault Tolerance)
You could find more info from Microsofts MSDN library e.g. Serach from MS MSDN Library on "DCOM", or DCOM Overview.
The OPC specification could be downloaded from the ion.org>OPC Foundation, specifically you could find a white paper on OPC, DCOM and Security as pdf file.
Hope this helps
Roland
PS: If someone needs more info on Modbus specification you might find it on Modbus.org

Communication from a fieldpoint also acting as a OPC server to a simatic 545 through serial?

Hi...
I'm supose to control a breweri, and right now it is controlled by a simatic 545.
Is it possible for fieldpoint and connect directly to the PLC with OPC using serial?
I have the software to run NI's OPC server, but haven't bought a fieldpoint yet.
So i was wondering if this is possible to reuse the I/O oirts of the PLC instead of buying new I/O boards for the fieldpoint, which is very expensive.
Thanks..
Carsten Toft
Aalborg University Esbjerg, DK

The easy scenario is to use FieldPoint with the OPC server to provide distributed I/O for your HMI/SCADA application. The same HMI/SCADA application can communicate via OPC to the Simatic 545 thru serial. In this scenario, the data move from FieldPoint to Windows XP to Siemens. For slow processes and current computing technology, this scenario typically works well.
If you need FieldPoint to communicate directly over serial to the Siemens Simatic, you will need communications support in LabVIEW RT for the Simatic PLC. Typically what is recommended is to use a Modbus gateway and the LabVIEW RT modbus VIs to communicate Modbus protocol from Fieldpoint to the gateway, and the gateway then communicates over serial to the Simatic.
here are the modbus vis
http://sine.ni.com/nips/cds/view/p/lang/en/nid/201711
here is a reference for gateways
http://www.woodhead.com/products/automation/gateways/
Preston Johnson
Principal Sales Engineer
Condition Monitoring Systems
Vibration Analyst III - www.vibinst.org, www.mobiusinstitute.com
National Instruments
[email protected]
www.ni.com/mcm
www.ni.com/soundandvibration
www.ni.com/biganalogdata
512-683-5444

Multisim Design Project Help

I was wondering if anyone could help with a design I'm working on. It is on NI Multisim 13.0 and I am planning to use the design for a breadboard, also. So here are the basics of the design:
It is a railroad crossing.
There's a traffic light located at the railroad crossing.
The track's used by both east and west heading trains.
There are three sesnsors along the railroad track: one's at the crossing and one on either side of it (both are each 1/2 mile from the crossing.
At all times, each sesnor indicates whether some portion of the train is at that location.
Trains may be up to 1 1/4 miles long, so that at any moments 0, 1, 2, or 3 of the sensors may be active.
Normally, the traffic light is green. However, when a train aprroaches within 1/2 of a mile of the crossing, the traffic light must go yellow for ~2 seconds, and then stay red until the train is completely past the crossing.
Trains do not reverse directions while in the vicinity of the crossing.
The input summary: 3 (the sensors at the crossing and at either side of the crossing, 1/2 a mile from it).
The output summary: 3 LEDs (traffic light; can be colored, like red, yellow, and green).
There's also a sensor in the road at the crossing, which at all times indicates whether there's a car crossing the tracks. On either side of the crossing, 1/4 of a mile from it along the track, there are two warning lights (which warn trains if there's a car on the crossing).
The additional input summary: 1 switch (the car sensor at the crossing).
The additional output summary: 2 LEDs (Warning Lights).
I am having trouble getting a grip on what the project is asking to do. If you could explain possibly the logic on multisim used and a general outline of what the design would look like on the multisim and on the breadboard. All helpful answers are good. Thank you all for any helpful answers that are good.

There are many possible approaches to this project, and I think there is not a problem with Multisim but rather with designing an electronic control system in general.
Of course this problem can be solved using your own circuitry which would consist of sensor interface, control logic and output interface. This can be done hard-wired by logic circuits. Another approach would be using a simple microprocessor and programming it. You can also use pre-fabricated devices which exist as PLC (programmable logic controllers). There are quite simple PLCs consisting of a single device and limited number of inputs and outputs (sometimes expandable), and more sophisticated ones with CPU modules, input and output modules. Most manufacturers offer a development software, and pretty often this allows for designing with (virtual) logic components such as AND gates and OR gates.
Whatever approach you take, you should be familar with designing logic circuitry and (if necessary) designing interfaces for the necessary sensors. When using a PLC, there are many sensors available with PLC compatible outputs which can be wired directly to the PLC inputs.

Direct communication with SIEMENS PLC

I am trying to establish a direct connection with a SIEMENS S7 PLC. I donot want to use any card or profibus etc. I want to do it through the Serial Port.
I have used the IA server kit when communicating with SIEMENS S5 for which I used AS511 protocol. I would like to know if there is any such protocol for S7.
Please Help!!

Hi.
I'll try explain it.
All Simatic S5 PLc's processors (CPU90 ,CPU100) have got serial (current loop converted to RS232) physical inteface as standard.
You can program PLC's or communicate with its by AS511 protocol.
S7 Simatics processors (CPU 3xx, CPU4xx) haven't got RS232 interface as standard. RS 232 interface occurs in forms of interface module connected to the rail (slot) and doesn't serve any protocol (simple chracters exchange).
You can program PLC, observe/modify I/O, variables, etc. only by standard RS485 interface using protocols MPI or PROFIBUS (PPI/MPI for Simatic S7-2xx CPU's).
You can try exchange data between Labview and S7 PLC by serial in characters form, but it is very difficult and inconvenient (you have to w
rite own driver for Labview and program for S7).
Another solutions:
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2.connection thru OPC server (PLC->PC by PROFIBUS card->OPC server->Labview by Datasocket)
I think second solution is more comfortable.
See also:
Connecting LabVIEW to an OPC Server through a DataSocket Connection
Regards.
Romek.

PLC Direct with Lookout 4.0.1

I am running the following
Windows 2000
PLCDirect 250 with ECOM module on ethernet
Lookout 4.0.1
DSPlus software ($349) from Automationdirect.com (Beta now but shipping
soon)
I was having problems but all is working now all is working now.
Here is what I believe the problem was.
In Windows NT4 you can leave Lookout Direct or prior Lookouts on your system
and everything will
work just dandy. But this doesn't work in Win 2000 for some reason.
Here is what I did to make it work for me.
1. Uninstall Lookout, Lookout Direct, and DSPlus.
2. Delete all folders that uninstall left, (Probably not necessary, but why
not to be sure.)
3. Restart Win 2000
4. Install Lookout 4.0.1
5. Restart Win 2000 (Probably not necessary, but why no
t to be sure.)
6. Install DSPlus into same directory as Lookout 4.0.1
7. Restart Win 2000
8. Start Lookout 4.0.1 and all works perfectly so far.
This combination with the built-in Web capability of Lookout 4.0.1 is just
awesome.
Thought this might be useful to you in the furture.
Dave LaPoint

Thanks for the troubleshooting steps. This is exactly what people need to have access to.
Thanks,
Zork

How do I write to A-B PLC through 1761-NET-DNI?

Thanks, Emilie, for your previous response. I guessed that was the case, but as I'm new to DeviceNet, I was unsure.
I am still having problems communicating with the Allen-Bradley PLC, and am not sure whether the problem is with my LabVIEW code or configuring my DNI. I have attached a sample of the program I'm using to send a message to my PLC. Do I have the correct idea regarding how to send messages to the DNI network through my NI-DNET card? I set up the DNI so that the I/O page is in the Bit register file, and have programmed the PLC to turn an output light on if a certain bit in that section of the register file is logic-1. I use my LabVIEW program to send a message to that bit, but the light does not go on. Are there any obvious problems with my LabVIEW code? Thanks.
Mark Leusink

Hi Mark,
I took a look at your code, and for the most part, it looks very
good. There are only two things that I can see that may be
causing some issues. The first and most obvious is that you are
not using your error inputs and outputs at all. If you take a
look at any example program, the pink error cluster is wired through
all the VIs. This is always good practice, because the error
message returned from these VIs usually can point us in the right
direction of getting the error solved. If you do not wire this
through, the error may be lost completely. There may even be an
error message occurring in this program that we are not seeing that
could help us figure out why your device is not responding.
The other point of interest that I saw was in the inputs to the Convert
for DeviceNet Write.vi. The DNetDataIn input is left blank, which
is fine, except that you also have a byte offset of 1 as an
input. DNet Data is in an array format, and this VI will take
other data and convert it into DNet data, placing it in the data array
wherever you specify in the byte offset. Since you have nothing
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0's. The byte offset is 1, so it skips over the first byte (at
index 0) and then places your data starting at byte index 1. This
may be the way your device is expecting the data, but if you want that
data to be at the front of the data array, then you need to wire a 0
into the byte offset. Otherwise, the data being sent out starts
with 0's.
Hope this helps!
john m
Applications Engineer

Data plc labview

First off thank you for anyone that reads this, I am very new at LabVIEW, and I think this maybe a trival question but I am not sure.
I am building a test bench to measure the torque vs angle of clutch disc to find the hystersis. I am confedient that my program is fine to record the data. I am usin a servo motor to apply the torque and when the torque gets to high I want the plc to shut off the servo motor. I want LabVIEW for the data acqusition but the plc for the control. I have no experience with modbus. I was wondering if i could share the output from the torque transducer with both the plc and LabVIEW or would this weaken my signal and affect my data? The torque transducer is a mv/v output, the tourque transducer is TRS-20K from transducer techniques. I will be using a PLC from automation direct, and a NI-9237.
http://www.transducertechniques.com/trs-torque-sensor.aspx
Thansk for your time
Solved!
Go to Solution.

Hello Carl,
It sounds like all you need to do is send an on/off signal to a PLC. Any communication (modbus, OPC, DataSocket, EPICS) that occurs between the host PC and a PLC is non-deterministic. These will all result in some form of varying delay.
The USB-DAQ will be able to output a signal from your computer to your PLC. If you program the PLC to record the signal from the DAQ to control your transducer, this should work. There will be a delay between when you send the output signal to the DAQ and the PLC reacts. This delay will not be deterministic. It will vary depending on your current operating system usage. With that being said you should be able to get a response within 100ms.
How fast are you looking to control this PLC? Do you need the control to have a deterministic/consistent delay? Are you doing closed loop control testing?
Hypothetically, if your computer crashed while the DAQ is in applying torque, you would still be applying torque until you reset the device. If you continually torque, will this damage any of your setup? If so, I would recommend implementing some kind of watch dog timer on the PLC which can be reset by the DAQ.
If you are looking for a deterministic solution, I would recommend using a cRIO with LabVIEW Real-time.
Regards,
Thomas C.
Applications Engineer
National Instruments

PLC Communications with Labview

How do I view and record data from my plc to labview, currently we are using autmation directs DL205 with the 260 processor

If the DL 205 communicates through the Modbus protocol, you could use the Modbus library. This library consists of a bunch of VIs which can be used for Modbus communication. Think of them as advanced Serial read/write VIs. However, if you are looking into monitoring, datalogging and controlling the registers, then I would recommend the LabVIEW Datalogging and Supervisory Control Module. Using shared variables, you can then easily bind, control and talk to the registers and most of the work is taken away from you.
If the DL 205 doesn't communicate throught the Modbus protocol, then you would need an OPC server (like the NI Industrial Automation OPC Servers) and the LabVIEW DSC Module. You can then communicate from the LabVIEW DSC Module with the OPC server.
Message Edited by Adnan Z on 03-15-2007 10:27 AM
Adnan Zafar
Certified LabVIEW Architect
Coleman Technologies

Is there anyway to make a PC look like a PLC on a Profibus network?

We currently have a PC based data acquisition system. A customer has asked us to integrate the PC into their PLC (Profibus) network and make it appear as though it (the PC) is a slave on the profibus.
I have found some interfaces that convert profibus to ethernet but haven't found anything, short of the NI Applicon boards (and others), that allow me to go the other way. As I only want to be a relatively stupid slave on the profibus, I was wondering if there isn't a more economical solution.
Any comments, suggestions, directions, etc. would be helpful as I'm starting from scratch and am not sure where to go with this...
Kind Regards,
Eric

Hi, Del Conte
I've looked at: http://www.sea.siemens.com/machine/products/cnc/prod_810d.html#1523 and have seen that this CNC consist of Numerical processor, power units and has integrated PLC S7. And there is possibility to connect this PLC to PC through Profibus. I didn't remeber if inside of Softnet exist OPC Server. You can check it in Simatic NET Configuration Console. Siemens doesn't provide any drivers for LV to their CP5611 card. Comunnication idea relay on using OPC Server. OPC Server establish and continue data exchange between PLC and PC. Labview has OPC Client features by means of DataSocked or DSC module to get/put the data. If you give me your PLC configuration (series numbers of all PLC modules on the rack from left to right ,e.g. - 6ES7315-2AG10-0AB0) I can prepare to you connection configuration PLC - PC. Moreover you have to have STEP7 Programming Software and Simatic NET Software to download PLC configuration into PLC.
Regards. Rumcajs

TRAMAS DIRECTAS A UN PLC

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