Lookout modbus plus performance

I'm running 9 Schneider Electric PLCs Compact 265 connected to Lookout v5 PC via modbus plus. I have cyclic stalls of transport, each 50 secs or so, which last for 3 or even more seconds. I've tried all the settings there are on modbus object in Lookout, but with no success, only different graph shapes in performance monitor (you can have a look at graphs at the end of mail). Even single PLC on network (with others shut down) freezes the communication for more then second, which is unacceptable since I need to refresh my data at least each 350ms.
I've considered 3 things:
1. PLC underperforms
I've checked scan time in PLCs, they're all running smooth with scan time under 90ms. This time doesn't increase even during modbus peaks, I've reduced watchdog to 100ms and it never triggered. Looks to me like plc has more than enough time for modbus, so plc should not be the problem.
2. PC underperforms
Hardly a problem, PC running under 5% most of the time, never goes over 50% no matter what I do.
3. modbus underperforms
Statistics show no garbled or timed out frames on any plc, so wiring should be fine.
PLC uses 130 registers of memory (type 4 – holding register). With all registers back to back (no slack between registers), this should mean that all the memory can be transferred in 2 frames. This also means total data load per sec should be
9 plcs * 3 refreshes * 130 reg * 2 bytes = 7030 bytes.
Even with overhead included, this is so little compared to theoretical 120 kbytes modbus plus should be able to perform, so nothing else for me to do but scratch my head.
I've checked Lookout source for any loops which could initiate some read or write at 50sec cycle, but there's nothing even close anywhere in program.
Am I missing something? Can anyone tell me why modbus freezes my system?
Bye everyone,
Darko
SVETLOST TEATAR

Hello,
It’s been a while since I last checked the forum, but in the meanwhile I’ve resolve the problem.
The solution lies in modbus.ini and the way modbus object communicates with modbus secondary, an issue not properly covered by help and ni.com. Unless defined otherwise in modbus.ini, modbus object will refresh all of the configured memory points in your plc each 50 or so polls (I can’t remember which is the default value). This can be a problem if the number of memory points is large, because it congests modbus and creates performance stalls.
You can read more about this here: Lookout Driver Objects - Custom INI File Settings (http://zone.ni.com/devzone/conceptd.nsf/webmain/E54F75254BBE772786256CFC00700B5F).
Thanks everybody for joining in.
Bye,
Darko

Similar Messages

No ISA slot available in PC. How can I use PCI-85 Modbus Plus card with Lookout?

My application is to communicate with two Modicon PLCs using Modicon's ModBus Plus (PCI based PCI-85) network card inside my PC, and using Lookout as an SCADA software. Since there is no ISA slot available in new PCs, I can not use Modicon's ISA-85 Modbus Plus networc card. But Lookout does not support PCI based PCI-85 card, how can I use PCI-85 card then, with Lookout? Why doesn't Lookout support it? I asked the following question from from the Modicon's representative about it:
If I purchase Modbus Plus Driver Suite CD (SWMXDS001, 05, or 10 etc),will I be able to use Lookout SCADA software (by the way, it supports standard MB+ prtocol) for my application? If yes, can I use any version of an
y of the ISA, PCI, or PCMCIA based MB+ card?
His answer was:
The Modbus Plus Driver Suite will talk to any version of card, PCMCIA, ISA, and PCI. The question now is will the SCADA package you are
planning on using be able to talk to the Modbus Plus Driver Suite? You must contact National Instruments and ask them if they support Modbus Plus, and if
they used the MB+ system developement kit to develop their product. Or if they wrote their own MB+ drivers, do they work with Modicon hardware?

Hi,
currently Lookout does not support the PCI-85 card. The only card supported for Modbus Plus is SA-85. Please see for further information:
Where can I Find Drivers for Communicating to PLCs, RTUs, and Other Industrial Hardware?
How to configure the SA-85 card for Modbus Plus
Hope this helps
Roland

Immediately write outputs - more on modbus plus performance

more on modbus plus performance
I have more dilemmas considering modbus plus. I'm trying to reduce the unnecessary traffic as much as possible, so I've unchecked "immediately write outputs" in advanced settings for modbus plus hoping that lookout will write to plc only when modbus object is polled. However, it seems that it doesn't happen that way, looks to me like lookout is writing to plc poll or no poll. I need to cut down the traffic because I have delay in system response and I'm considering lookout's share in it.
I have a feeling that making a system with deterministic response (which should be one of mb+ highlights) is quite cumbersome and sometimes impossible.
Can anyone comment on this issue and maybe share ideas for improving modbus response time? Is there anything about modbus plus and lookout on ni.com that I'm not aware of?
Darko

By default, Lookout writes Outputs immediately (without waiting for the poll). BUT, if you uncheck the "immediately write outputs" setting, it should write only when polled. If it's not doing this, it's a bug -- can someone at NI verify this?
Couple of things you can try for improving communication performance:
1. Make sure you're not writing outputs every-so-many polls (unless you really have to). By default, Modbus Object writes the Outputs every 100th poll -- even if none of them have changed. Use the Modbus INI settings to change this behaviour:
http://digital.ni.com/public.nsf/allkb/2E64D5CF87CA6A1086256BB30070DC1A
2. If you have some IO points which don't need to be read as fast as others, use a second Modbus object for these with a slower poll rate (but on the same address, etc.).
3. Use an appropriate update deadband for your analog reads -- you can filter out "noise" from data this way. Note that the IO are still read every poll, but aren't propagated to the rest of the system unless the deadband is surpassed.
Hope this helps,
-Khalid

Lookout Modbus Ethernet driver for Do-More PLC?

I see AutomationDirect has now come out with a Do-More PLC CPU that uses DirectLogic 205 hardware. Their documentation states that the new CPU Ethernet port communicates with protocols that include:
Modbus/TCP Client (Master) and
Modbus/TCP Server (Slave)
Would the Lookout Modbus Ethernet driver communicate with this?
Solved!
Go to Solution.

Yes, Modbus driver supports ethernet
We us the ECOM-100 and MB-Gateway
Forshock - Consult.Develop.Solve.

I get error, "can not load NETLIB.dll" on a MODBUS Plus Object.

I have 18 Modicon PLCs in my network, using LOOKOUT for my HMI. Only one PLC gives this error.
Can you help me?
J. Bubba

thank you !
i have tried to make new installation of lookout in eveluation mode, with only one point in ModBusPlus
the problem is the same but after i have added manualy the dll and apparently this is a good solution
another problem is the selection of serial port, in modbus object thi is possible only in serial ModBus option but non in ModBusPlus option
i think to modify the port in .lks files and recompiling this, is correct ?
the next week i tried with the scada the same procedure
because in my (two different) computer the installer work [apparently] fine but not install netlib.dll ?
intel processor, winXP.p SP2 without any firewall, one without antivirus (the scada) and one with avast professional (the tried machine)
is a problem in modplus plus driver in this version (see precedent post) ?
is made specific patch or document by NI ?
B_N_

Is there a Modbus TCP driver built into Lookout ?

Is there a built in ModbusTCP driver or do I need to add-in a third party OPC server.
Thanks!
Greg.
Schneider Electric.

The Modbus object in Lookout supports Modbus RTU/ASCII, Modbus Plus, and Modbus TCP. I am using all three protocols with great success.

How can I edit the database in Lookout OPC Modbus driver OPC sever with the address that has a write attribute?

When I use Lookout Modbus driver OPC to communicate with my instrumnets, I edited the database number such as 41202 that has a Write attribute in my instrumnet manual, the OPC explorer got bad data, and the OPC server gave the illegal address alarm, when I input the address such as 41203 that has R/W attribute, it worked very well. Is there a way to fix this problem. When I used other OPC server, there was no this kind of problem. Thanks!

Thanks for your suggestion. I checked the Modbus manual of my instrument, the register is 16 bit. I tried to edit the data according to the Modbus data member in lookout modbus drivere server for several different member, but the OPC still gave me the illegal address. I think the problem may be produced by their attribute, for the address 1201 and 1202, they have the write attribute, for other addresses, they have W/R attribute, and they can be read or write through Lookout OPC server perfectly. when I used the demo OPC server from other company, it can work well, but it is not convinient for me to use Labview when I use that software. I prefer NI Lookout OPc server. I am using the Lookout 4.5. I am wondering whether the Lookout has some shortcoming when I
use the Modbus driver. Please give me any suggestion, is there any newest version of Lookout OPC sever? Thanks!

Which multinational companies are using Lookout software, how reliable it is?

What PCI or ISA board or a module is required to communicate the Lookout with the Allen Bradley PLCs using ModBus Plus protocol?

Here's a sample listing of Lookout installations:
http://digital.ni.com/csma.nsf/display?ReadForm&lookup=Lookout&view=InternetCSbyProdLine&node=124100...
Hope this helps,
Khalid

Has anyone used Lookout 4.5 with Motorola MOSCAD?

If so, please send me an e-mail at [email protected] My question is, Can I use the ModbusMOSCAD driver to talk directly to a RTU in the field via radio without using a FIU or do I have to use and FIU and talk modbus to the FIU and let the FIU gather the info from the field?

Here's what the Lookout online help says:
The ModbusMOSCAD object class works with Motorola MOSCAD PLCs and RTUs. It also uses the Modbus Serial (ASCII or RTU) or Modbus Plus communication protocol, but its data members reflect the address of Motorola MOSCAD devices.
It looks like you should be fine using the modbusMOSCAD object in Lookout

200 Point Limit Exceeded

We only have about 30 actual datapoints, but the PLC is handling all engineering unit conversion and alarm checking. So for each datapoint requires that Lookout set or monitor 5 real values (Hi and Lo setpoints, Engr. conversion constants, and measured value) and 3 flags (hi and lo enable alarms and alarm indicator). Which adds up to about 250 references on Modbus Plus which exceeds our 200 licenses limit. How can I get Lookout to recognoze that there are only 30 actual datapoints?? We are using Lookout V5.1
If this is not possible, how do I increase the license point limit and how much does it cost???

Hello, In fact you do are using the 250 points that you mention. An IO point is not only the members for the PLC, but anything that has access to Citadel and Drivers.
Check the following Link to learn how many IO points you have. Said this, you need to upgrade your license for more IO points.
Ricardo S.
National Instruments

Labview 7 install errors

I am getting the following errors while trying to install labview 7.0 and DSC engine on a gateway laptop with a pcmcia modbus plus card and win2000. I have completely uninstalled labview 6.1 and 7.0 and deleted the directories and still get installation errors. Does anyone have any ideas??
Attachments:
errors.zip ‏10 KB

yes i do. I have it setup where I don't need to enter the administrator password. It may be an issue with win 2000 and the texas instruments pci-1420 cardbus controller. I am having a conflict with this and my pcmcia modbus plus adapter card. The computer is setup to multi-boot and the modbus plus adapter works fine inside win98. I have installed service pack 4 for win2000.

Cannot lauch project, class error messages

The project was originally configured in LookoutDirect, then converted to Lookout 6.2.
One one computer I have a seperate Runtime and Development packages. This computer has been working satisfactoraly for two months.
Insatlled second runtime software on computer two, but cannot launch project because of class errors.
Can I copy the entire National Instrument folder from one computer to the other to correct this.
thanks
John Peterson
Solved!
Go to Solution.

Problem solved
Believe drivers are DSComm4.cbx and Meter4.cbx, but don't bother moving them. Tried every conceivable location.
You must INSTALL the driver on both computers.Driver from Automation Direct (PC-DL-PLUS LOOKOUT DIRECT PLUS DRIVER OBJECT SFTWRE)
From the responses I think their is more than one with the problem.
Also make sure the tages are not pointing to the computer name. Tag path should start with "..\" or "..\..\" (test on yours) to work on both computers. Computer name appears depending on how you drill down to the PLC address. This doesn't stop the project, just gets rid of the red X's on the second computer.
Thanks for your responses
John Peterson

Communication problem with Modbus object in Lookout 3.8

What means the error code 06 besides the following alarm message NO COMMUNICATION RESPONSE FROM MODBUS SECONDARY ? Lookout runtime-express version 3.8 build 7

Greetings,
The alarm message "No Communication response from modbus secondary" means that communication cannot be established between the modbus object and your external device. Verify that you have set up the serial port settings properly and that you have configured the modbus object. Verify that your external device is functioning properly and connected to the PC. If all of these things are ok, you may need to increase the receive gap of the serial port settings and the receive timeout of the modbus object. There is a tutorial on the web which outlines the troubleshooting steps for communication in Lookout.
http://zone.ni.com/devzone/conceptd.nsf/webmain/033CD84BAC7E1E7586256A3300756284?opendocument
I hope this information is helpful. Have a good day!
Patrick R.

How to implement Modbus Ethernet communication in Lookout, if we want to simulate the PC as PLC ?

Problem Description :
Dear Sir,
We are doing a project where we are using Lookout with
Front end Modicon PLC. The communication is by
Ethernet, using Modbus.
Since the installation is at a distant place, we wanted
to use another PC (running Lookout) to simulate the
PLC. For this, we tried to communicate
a: the server Lookout PC running Modbus Ethernet mode of
Modbus object as Master
b: with another PC (for simulating the PLC) running
Modbus Slave
We did not get any communication. (we have given the
details of what we have done, at the end of this email)
We also tried connecting the above 2 PC's as
a: the server Lookout PC running Modbus Serial mode of
Modbus object as Master
b: with another PC (for simulating the PLC) running
Modbus Slave object
Again we did not get any communication.
If instead of PC (b) we connect the Modbus simulator to
PC (a), there is no problem in communicating
Please let us know how to go about establishing the
communication between 2 PC's using Modbus serial,
and Modbus Ethernet. A detailed step by step procedure
would help us a lot.
Thanking you
Warm Regards
Raja Mahbubani
Procedure of our trial with ethernet.
This is what we have done in detail.
On PC A:
We created an object (Pot) and connected it to
the modbus data member of the modbus object say 40001. In the
properties of the modbus object we selected modbus ethernet mode
of communication and in the IP address field we wrote the IP
address of the machine B to which we are trying to communicate
i.e. 152.63.50.2.
On PC B: we tried the following two methods
Trial 1 : We created a modbus slave object and
inserted an expression for the same data memeber to which the
object was connected hoping to get the value of the pot of machine
A on machine B.
Trial 2 : We created a modbus object on machine B and we wrote
the IP address of machine A and inserted an expression for the
same datamemeber to which the object was connected hoping to get
the value of the pot of machine A on machine B.
NI Software : Lookout
Version : 4.0.1 or 4.5
OS : Windows 98
NI Hardware : N/A
Drivers : N/A
Other Hardware/Instruments : N/A
CPU : Pentium
RAM : 64
Vendor : S-Tech
Customer Information :
Raja Mahbubani
Theta Controls
IN
[email protected]
Ph: (+91) 20 4222556/7

The ModbusSlave which comes with Lookout currently supports only Serial communication. So, you cannot use Ethernet between your two PCs. At least not with Modbus Master-Slave setup (if you must speak Ethernet between the two PCs, IPASCII object lets you do that, but then you'll need to implement your own protocol).
Since all you want to do is simulate a Modbus PLC on a PC, you can use the Serial mode of communication for now. And later on just modify the Object in your Server Lookout to use the Ethernet mode.
For setting up a Serial Modbus Slave, use a null-modem cable between the two PCs (lines 2 and 3 are swapped). On your PC 'B,' create the Modbus Slave object with the right COM port for that PC. And on your PC 'A' create the regular Modbus Object as if you w
ere connecting to the Modbus Simulator box. The only difference here is the cable. The simulator box uses a straight-through cable whereas the Slave needs a null-modem cable.
Hope this helps.
Rgds,
Khalid

Lookout 6.5 critical crash - writes to random modbus addresses

Hello,
We are experiencing a rather critical problem with Lookout 6.5. The proces file contains approximately 148 Modbus/TCP connections, some overview panels, a properties panel which uses a symbolic link to retrieve properties from a certain modbus object.
Seemingly random, Lookout crashes during operation (with the Windows send/don't send window). When this happens, the second before the crash actually occurs Lookout starts writing seemingly random values to addresses to all the modbus devices. Some to addresses which are connected in Lookout, and to some that are not (even to addresses that actually don't exist on the device, which causes it to return an exception). The addresses do seem to be in an increasing sequence (i.e. it starts at 500, then starts writing further until about 850). Values I've seen are mostly 0, but also 256, 2308, 512, 2048, 3844.
I've attached a packet capture log which shows the write commands Lookout is sending.
Does anyone have any idea what could cause this crash or things I can check?
Attachments:
dump.txt ‏175 KB

Also uploaded a second dump file as Randomwritecrash2.zip - I'll keep uploading dump files in sequence.
Crash data from this dump:
(1328.bd4): Access violation - code c0000005 (first chance)
First chance exceptions are reported before any exception handling.
This exception may be expected and handled.
eax=01cbcd1a ebx=00f70000 ecx=3e720012 edx=3e720013 esi=00f70838 edi=00000009
eip=7c902a9d esp=0013f4f4 ebp=00f70838 iopl=0 nv up ei pl nz na po nc
cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00010202
ntdll!tan+0xcf:
7c902a9d 8b18 mov ebx,dword ptr [eax] ds:0023:01cbcd1a=????????
0:000> kb
ChildEBP RetAddr Args to Child
WARNING: Stack unwind information not available. Following frames may be wrong.
0013f4f8 7c91020e 00000009 00f70838 00f70000 ntdll!tan+0xcf
0013f510 7c9101db 0013f744 7c90e920 7c910228 ntdll!RtlAllocateHeap+0x14a
0013f528 7c91019b 00f70838 00000013 0000003f ntdll!RtlAllocateHeap+0x117
*** ERROR: Symbol file could not be found. Defaulted to export symbols for C:\WINDOWS\system32\MSVCR71.dll -
0013f754 7c3416b3 00f70000 00000000 0000003f ntdll!RtlAllocateHeap+0xd7
0013f794 7c3416db 0000003f 7c3416f8 0000003f MSVCR71!_crtLCMapStringA+0x305
00000000 00000000 00000000 00000000 00000000 MSVCR71!_crtLCMapStringA+0x32d

Lookout modbus plus performanc​e

Similar Messages

Maybe you are looking for

Lookout modbus plus performance