November 2012 Genius Webinar Questions

1. Where can we find a definition of the parameters used in the path?The path is explained on page 184 in Chapter 4 of the RSLogix 5000 Controllers General Instructions Reference Manual.

Please refer to Answer ID 22562 - MSG - CIP Paths: Brief summary for a brief summary on MSG instruction CIP paths and pathing.

2. If you use the "Browse" function; what do you see?If you enter in all of the hardware necessary to properly reach your finale destination device (in the I/O Configuration), you can use the “Browse” feature to select the target device in the path. Only the target device name (as entered in the I/O Configuration) will be displayed, but the entire path structure is retained in the background of the MSG instruction.

3. What is the 2 in front of the IP address for the path?Once a path leads up to a particular module, you have to instruct the MSG instruction to actually travel out the channel (out on the wire or network). The number 2 is used to push the MSG out the communications module.

4. What about MSGs to "other than controller" devices, e.g. Windows box or Unix box or mainframe?Please refer to Answer ID 7414 - Receiving an PLC-5 type unsolicited message from a Logix 5550 processor through Ethernet and Answer ID 8649 - Receiving Unsolicited CIP From Logix Via Ethernet to address this subject.

5. For the overhead time slice, do other items affect what it should be set as, such as data historians, programming and HMI connections?The Communications time slice includes all communications (outgoing and incoming). If you have an application that has intense communications coming from other outside sources, increasing the time slice can help and possibly improve communications.

6. How does redundancy affect memory usage?Please refer to Answer ID 28972 - Understanding ControlLogix Redundancy Memory Usage to address this subject.

7. How do you suggest controlling message execution if not with a Timer Done bit?Any conditional logic can be used to trigger a MSG instruction. Just make sure that you do not use up all of the available buffers.If you need a MSG to trigger continuously in a Logix controller, you can simply use an XIO with the address of the MSG’s .EN (enabled bit)Please refer to Answer ID 42582 - Example of a continuous repeating message in SLC 5/03 or higher processor for the SLCTM and or MicroLogixTM controllers.

NOTE: Setting up a continuous MSG will always consume one buffer.CAUTION: Using a TMR Done can fill up all available buffers with one MSG instruction provided that the trigger executes prior to the MSG’s completion.

8. Tim mentioned that timers are not the recommended means of triggering MSG instructions. Will he address some good practices for triggering MSG instructions?Please refer to Answer ID 42472 - Cascade MSG instruction Example in RSLogix 500 for several examples of Cascaded MSG instructions using RSLogixTM 500 for both a SLC and MicroLogix controller.

9. In the MicroLogix family, how do you get to the advanced controller properties to see the memory usage for messaging?The Memory Estimate Tool that was covered in the Webinar is only available in the Logix controllers.To perform a similar function in a SLC or MicroLogix program, verify the project and then open up the Controller Properties. As long as the program is not too large, the “Memory Used” and “Memory Left” fields will indicate how much memory is available. If the program is too big, RSLogix 500 should have indicated that the program could not be compiled due to insufficient memory. RSLogix 500 will not indicate the amount that you went over.

10. When setting up the MultiHop communication, what if you want to read across to a DH+TM to Ethernet through a DHRIO gateway? How would you accomplish the setup to go through the gateway?The MultiHop tab actually becomes a path generator (similar to the path that we entered in the Logix controllers). Once you have defined your first line, press your computer’s INSERT key in order to add the next step of your path. You will end up having one entry for each step of your MSG path.

11. Can the message buffer be increased for PLC-5®?You cannot alter or increase the number of buffers available in a PLC controller.

12. Can you discuss the advantages/disadvantages of using a MSG instruction versus produced/consumed tags?Produced/Consumed tags are used when there is time-critical data that needs to be shared between two devices and if it doesn’t happen, we want to know about it immediately.MSGs are used when a specific time is not at all critical. Each produced/consumed tag will use up an individual CIP connection (resources) in the communications hardware (Ethernet/ControlNet communication modules) in order to perform their data exchange. Depending on the hardware and firmware revision in use, connections can be a limiting factor.

13. In Logix, for the path, can't you press Browse instead of typing 2, IP address?See previous Question/Answer #2.

14. Do you need a send and a receive MSG block? One in each processor?You only need one MSG in one of the two processors. You could either send data using the Write or get data using the READ MSG command.

15. Tim mentioned that a Timer Done bit was not recommended but never said what was? What is the best method to trigger a reoccurring message?See previous Question/Answer #7 and #8.

16. Can we add messages while in the online edit mode or do we have to be offline and download the new program?As long as the controller you are using supports online edits, the MSG instruction can be edited and or created while online. A SLC/MicroLogix app will not allow the creation of data files while online, that is why I demonstrated the MicroLogix 1400 MSG example offline and downloaded.

17. How do I set up communication between SLC 5/03 with 1761 Net-ENI to the PC station, which is in the lab of PLC class?Please refer to Answer ID 19350 - Quick Start -- Getting Started with using the ENI Utility for help getting started with the ENI and its configuration utility.

18. Is there a Knowledgebase document on path configuration?See previous Question/Answer #1.

19. Can you please go over the 1,3,3 again?The MSG path for the advanced example that I used in the Webinar was:1, 3, 2, 123.123.123.2, 1, 1, 2, 123.123.123.3, 1, 01 (go to backplane), 3 (got to slot 3), 2 (go out the port), 123.123.123.2 (go to IP address), 1 (go to backplane), 1 (go to slot 1), 2 (go out the port), 123.123.123.3 (go to IP address), 1 (go to backplane), 0 (go to slot 0 – this is where Processor B was located)

20. Is it possible to use the "Browse" button in the Message Configuration to look through the RSLinx® network and find the correct path?See previous Question/Answer #2. The Browse within the MSG instruction is only used in conjunction with what is configured in the I/O Configuration and is not tied to RSLinx.

21. Does the Browse button not apply here?See previous Question/Answer #2.

22. What's the reason for using 2 in the path to go out the Ethernet port?See previous Question/Answer #3.

23. Is there a cheat sheet for what the numbers mean in the communication path for each PLC platform?

See previous Question/Answer #1.

24. Is it possible to MSG to a device on a DeviceNet NW and how would I do it?Please refer to Answer ID 16404 - DeviceNet Basics of Explicit Messaging for an excellent resource of information on explicit messaging over DeviceNet.

25. Is there a way to determine if a controller's (e.g. SLC 5/05) communication buffer is getting full to determine if message balancing is required?There are a number of status bits related to the MSG instructions and its execution that can be used to control your MSG execution. There is an EW (Enabled Waiting or Awaiting Execution) bit (available on all controllers) that can be monitored to inform you that the MSG actually made it into the queue. There is also a WQ (Waiting for Queue) bit (SLC/MicroLogix) that will inform you that there is currently no room in the active buffer.Please refer to Answer ID 19993 - Logix processors unconnected buffers for an example of how to get the high water mark of number of used unconnected output connections in the Logix controllers.

26. It was noted that a Timer DN bit is not recommended to activate a MSG instruction. What is a recommended means of toggling the MSG on a timed frequency?See previous Question/Answer #7 and #8.

27. Where in the world does one learn that 1 means backplane, 2 means go out the port, etc.?See previous Question/Answer #1.

28. Can we get a timing chart for the Logix MSG block? We are having advanced level issues with MSG blocks?If you click on the F1 key while on a MSG instruction, a help routine will open up. If you scroll down, you will see a timing chart that is also available in the manuals.

29. Why not use the Browse button when setting up a communication path?See previous Question/Answer #2. You need to make sure that you have defined and named all the required communication devices in the I/O tree.

30. I am trying to write a message between a 5/04 and a L61 through a 1756-DHRIO, how do you define a N10:0 length of 30 in a ControlLogix® platform?The Logix systems understand that SLC/MicroLogix Fixed addressing system, so you can target specifically the N10:0 address. The element size would need to be set to 30. Lastly, you would need to set your Logix tag up as an INT data type with an array dimension size of 30.

31. What is the correct practice for programming multiple messages in a Logix PLC?Best practice is to know how many buffers are available and how many your application is going to

require and plan accordingly.

32. What would the format for a CompactLogixTM path be for connecting to a MicroLogix through a router/firewall?You need to make sure that none of the TCP/UDP ports are blocked by any security measures in place. Please refer to Answer ID 29402 - TCP/UDP Ports Used by Rockwell Automation® Products for all of the TCP/UDP Ports Used by Rockwell Automation Products.

33. Can a L43 write Parameters to a PowerFlex® 40 via a MSG instruction?I would recommend calling our PowerFlex technical support group for help with this question.

34. What about EDS files and third-party devices?EDS (electronic data sheet) are used to identify devices communicating on a network. If you are using a specific network and want to see third-party devices show up in an RSWho/RSLinx screen you need to make sure that the device’s EDS file is installed. Please refer to Answer ID 18828 - RSLinx, RSNetWorx TM : General EDS File Registration for more details on EDS files.

35. How does a Timer Done bit cause too many executions of a MSG instruction?See previous Question/Answer #7.

36. I believe you mentioned that placing a Timer Done bit prior to a MSG instruction is not recommended. What do you recommend if you want the MSG to complete automatically every 10 seconds?See previous Question/Answer #7.

37. I’m converting a PLC-5 program to Logix and getting a bunch of errors. I’m assuming it’s because of the messaging and timer. The PLC-5 is reading/writing data to ControlLogix CPU, and we are planning to replace the PLC-5 I/O cards with a Logix CPU; that’s why we converted it to Logix. The errors are mostly Program Conversion Errors.In order to answer this, I would need to see what the rungs were and what instructions they contained. A PCE (Program Conversion Error) is a place holder to remind you that there is no direct conversion from the old format/program to the new format.

38. What are the processors on different VLAN's?I would recommend calling our Communications technical support group that supports the Stratix switches for help with this question.

39. Which one should I use usually: connected or unconnected?If you have a continuously executing MSG instruction that you require data as fast as it can be handled, and it is not critical as to require the produced/consumed method, then you could use connected. If you have an intermittent MSG that only gets triggered once every couple of minutes, it can be set to unconnected.

Using the connected method allows the quickest time between executions since the connection is kept open between the two devices. Unconnected closes the hardware connections after each MSG completion.If you use a connected connection on a MSG that only gets triggered every once in a while, you are keeping open a connection that does not need to be (there is no advantage).

40. What do you recommend to trigger the message instruction, if not a Timer.DN bit?See previous Question/Answer #7.

41. Is there a document detailing what all the Path numbers represent for each Logix processor? This has been difficult to find in the past for me in the help files.See previous Question/Answer #2.

42. Given: a PLC-5 MSG Read of a ControlLogix processor. What's required in the ControlLogix processor?If a PLC/SLC/ML MSG targets communication to a Logix controller, the Logix PLC will require PLC/SLC Mapping. PLC/SLC Mapping is a Logix feature that allows a program to link older style fixed address to Logix-based tags. Please refer to Answer ID 7355 - Setting up PLC/SLC Mapping in Logix controllers for more information.

43. Explain further why not to use timer DN before message instructionSee previous Question/Answer #7.

44. How many CIP connections are used when using the MSG instruction? Are unconnected messages sharing CIP connections?CIP connections are hardware limitations/mechanisms (how many communications request can be handled by a particular communications device/module). When a MSG is executed and data is passed between two devices, one CIP connection would be used by each device to pass the data. When an unconnected MSG is completed, the CIP connection that it was using will be closed and then made available for other unconnected MSGs to use. If two MSGs are triggered to the same device at the same time, two CIP connections would be used. Different hardware devices have different limitations. Please refer to Answer ID 39686 - Ethernet TCP and CIP Connections for a list some hardware limitations.

45. Where do you get a list of the commands?Highlight the MSG Instruction in the RSLogix 5000 programClick on the F1 key (for help)Scroll to the bottom of the help fileClick on Select MSG Type.

If the target device is a: Select one of these message types:Logix 5000 controller CIP data table read

CIP data table writeI/O module that you configure using RSLogix 5000 software

Module ReconfigureCIP Generic

PLC-5 controller PLC5 typed readPLC5 typed writePLC5 word range readPLC5 word range write

SLC controllerMicroLogix controller

SLC typed readSLC typed write

Block transfer module block transfer readblock transfer write

PLC-3® processor PLC3 typed readPLC3 typed writePLC3 word range readPLC3 word range write

PLC-2® processor PLC2 unprotected readPLC2 unprotected write

46. Where can I find a list of communication path commands?See previous Question/Answer #1.

47. When is it suitable to use connected or unconnected?See previous Question/Answer #39.

48. Can we get a brief explanation of how a MSG differs from BTW and BTR?A Block Transfer (read or write) is an older style communication method to a particular Remote I/O device (module) used to configure and properly operate. A regular MSG instruction is used to transfer data between two controllers.

49. Can you please briefly go over the communications path: 1,3,2, 123.123 etc... ? Specifically, what does each number means so I know how to manually build the path?See previous Question/Answer #19.

50. How about a PLC-5 to RSLogix 5000 MSG on DH+ to Ethernet?Please refer to Answer ID 118600 - Message Example PLC 5 to PLC5 via DHRIO and Ethernet for a detailed example of this.

51. Is writing MSG commands to other PLC different if I was to write MSG command to a drive that starts a motor?I would recommend contacting Drives technical support group for help with this question.

52. Can you read data on a ControlLogix with a MicroLogix 1100/1400?

You can MSG Read or Write to or from any Logix controller and either MicroLogix 1100/1400.

53. What if the previous MSG never gets done?There is a timeout value associated with the MSG instruction. Once the timeout expires, the MSG will error out. You can use the Done along with an OR of the Error condition for the next permissive to execute.You can also force a MSG to stop processing by turning on the associated MSG.TO (Time Out) bit.

54. We have a ControlLogix processor connected to a MicroLogix. We intermittently loose communication to the MicroLogix processor. What would you recommend to check?Set up some logic in the controller (executing the MSG) to trap the error code that is resulting and see if that gives us any more information.

55. Does a cached message continually send bits of data to the target port to keep both ports open?A Connected/Cached Connection will keep sending data (the same repeated data) over to keep the connection alive.

56. What is in the number of the Knowledgebase article that answers sample message instructions?When searching for a MSG example in our Knowledgebase include “Message Example” and the target and initiating processor, as well as the media that is in use. If a Knowledgebase article exists, that should get you to a number of examples that should be close.

57. What’s the difference between block transfer and CIP Data Table?A Block Transfer (read or write) is an older style communication method to a particular Remote I/O device (module) used to configure and properly operate. CIP Data Table is the method used to transfer data between two Logix controllers.

58. My system has 3 5/04's on it connected through DH+ network to 2 computers, a MicroLogix 1200 PLC controls another part of the plant. What is the best way to get the information to the RSView®32 program on the 2 computers?HMI and SCADA computers request their data from controllers so there is no need to setup and do any MSG’ing on the controller’s side. The controllers will respond to those devices.

59. For regularly sent data, is it better form to use a send MSG or a received MSG?There is no advantage of MSG Read over a MSG Write. Some applications may have controllers that are more burdened (incoming and or outgoing) than others and knowing which ones are burdened may help in selecting the initiating controller.

60. Is it better to do Read MSG or Write MSG?See previous Question/Answer #59.

61. Should OSR be used to make sure MSG is sent just one time?A one-shot instruction is not necessary based on how the MSG instruction functions. Only one trigger will result on a false to true transition of the MSG instruction.

62. How can you see all of the messages that a PLC is receiving?There is no way of monitoring all of the incoming buffers used by the PLC controllers.

63. If the target port closes, how does a cached message respond?The same MSG error codes are valid for unconnected as well as connected MSGs. If the connection is lost to the target device, a 7h or 16#0204 error code would result.

64. What Data Files are used for messaging?This varies from controller to controller:SLC uses a specified integer file (N), PLC/MicroLogix use a defined MG data file and Logix uses a MSG Data Type.

65. How many Ethernet buffers are required per Ethernet drive from a PLC-5 controller and what's the maximum number of drives?I would recommend contacting the Drives technical support group for help with this question.

66. Is there a good way to recover from an Error MSG bit if the processor was off?If a MSG error occurs due to the target controller being powered off, the resulting error code would be a 7h or 16#0204 (depending upon the controller). You do not have to do anything to recover outside of triggering the MSG again once the controller is powered back up. The MSG system will wait the entire timeout period of time before processing the error code, which could slow down other communications. You might want to incorporate some code in the event of the remote device being powered down.

67. Is there supporting documentation that outlines the format and a decode of what the individual numbers mean?MSG error codes are defined in the Programming Reference manuals – check with the specific controller’s manual for details. The Logix MSG error codes are listed starting on page 165 in the Logix5000 Controllers General Instructions Reference Manual.

68. What data exactly is communicated as part of the MSG function, and how is that configured defined?That would depend upon the protocol that is used. There is a DF1 Protocol and Command Set Reference Manual that goes great detail on the DF1 Protocol.

69. What type of Read is used to read data into a ControlLogix PLC from another ControlLogix PLC?CIP Data Table Read would be used to read tags from one Logix controller to another.

70. Are there any special considerations when messaging between two ControlLogix controllers over DH+?Make sure that you use the correct ports on the DHRIO module since it supports two.

71. How do you determine whether you write from the local PLC to the destination PLC or do a MSG Read at the destination PLC?See previous Question/Answer #59.

72. Where can we find the documentation that explains each part of the structure?You could start off by pressing the F1 key while on the MSG instruction and then refer to the controllers programming/reference manual.

73. How should messages be controlled if you have multiple devices that may be offline or disabled?If the target device is powered down, the MSG will eventually Error with a timeout error. This will slow down communications to other devices. Programming code could be setup to monitor a specific number of MSG errors (consecutive) and disable that MSG from triggering again until a certain time and/or some other condition happened to re-enable it. Another method if you have a HMI communicating on a network would be to have a button to press when powering down a controller and use that as a permissive to disable the MSGs.

74. Can you message to read Remote I/Os? Are there any benefits of doing so over using the unsolicited messages of UDP/EIP?We are planning on offering more MSG Webinars in the future that will cover this topic.

75. How do I setup MSG instructions with a third-party device? Which type of addresses should I use?This would all depend on what data types the third-party device supports and is a possible future MSG Webinar topic.

76. Can a MSG instruction be setup to work from a ControlLogix Processor and a PLC-5 ASB module?The only way a ControlLogix can communicate to a PLC is via DH+ or Ethernet.

77. Will a Timer Done bit used on MSG instruction affect the processor scan time?A Timer Done bit used to execute a MSG instruction will not have any better/worse affect over using any other condition to trigger a MSG instruction. Remember that the MSG doesn’t execute until the comms service section is reached at the end of the scan. It is done in this manner so that no matter how many MSGs have been triggered, the processor will maintain a reliable scan rate.

78. Can you provide a brief explanation on CIP Generic?Look for a future Webinar on using the CIP Generic option within the MSG instruction.

79. In your example, you did not click on "Connected". Why or why not?In my example, it was just going to be an infrequent execution – there was no need to make it a

Connected Cached connection. Not all MSG’s can be configured for Connected. The following table was taken from the ControlLogix System User Manual - Publication 1756-UM001M-EN-P

Chapter 7 - Manage Controller Communication (connections)

80. If I’m using an SLC to initiate the Read/Write messages and want to communicate to a CompactLogix, my communication command options in the SLC are only SLC and PLC-5®. Which one do I use? Is it possible to communicate to the CompactLogix?Yes, you can MSG from a SLC to any Logix (CompactLogix or ControlLogix) controller. The MSG type should be set to 500CPU in the SLC, and PLC/SLC mapping as discussed in previous questions/answers would also be required. Make sure to use an INT type tag in the Logix controller.

81. On the RSLogix 5000 processors, how do I know if I am allocating an adequate time slice (percentage) for communications? Is there a system value for monitoring how full the communication buffers might be?The following was taken from RSLogix 5000 help on System Overhead Time Slice:Enter or select the percentage of time the controller spends running its background tasks (communications, messaging, ASCII) relative to running your continuous task. The minimum allotment of execution time is 1 msec.

For example, at 25%, your continuous task accrues 3 ms of run time. Then the background tasks can accrue up to 1 ms of run time, then the cycle repeats. Note that the allotted time is interrupted, but not reduced, by higher priority tasks (motion, user periodic or event tasks, and others).

BACKGROUND CONTINUOUS At 10% - Background tasks time allotment = 1 ms, Continuous Task allotment =9 ms

At 20% - Background tasks time allotment = 1 ms, Continuous Task allotment =4 msAt 25% - Background tasks time allotment = 1 ms, Continuous Task allotment =3 msAt 33% - Background tasks time allotment = 1 ms, Continuous Task allotment =2 msAt 50% - Background tasks time allotment = 1 ms, Continuous Task allotment =1 msAt 66% - Background tasks time allotment = 2 ms, Continuous Task allotment =1 msAt 75% - Background tasks time allotment = 3 ms, Continuous Task allotment =1 msAt 80% - Background tasks time allotment = 4 ms, Continuous Task allotment =1 msAt 90% - Background tasks time allotment = 9 ms, Continuous Task allotment =1 ms

82. If I'm reading a ControlLogix to two MicroLogix 1400 different data, can I use the same source element? (even though the IP addresses are different)If you are performing a MSG READ to two different MicroLogix 1400 controllers (from a ControlLogix controller) you can read the same address (N7:0 - Source Element) from each device.

83. Is there a way to know when buffers are full?See previous Question/Answer #25.

84. If a message instruction is executed every 1 second and the processor scan time is 3/4 second, would the buffer still fill up?750ms is a long scan time for any controller. I am going to assume that you meant that the MSG takes ¾ second to complete. As long as the MSG system was able to handle the MSG every time at the ¾ second time frame, only one buffer would be used. However if something happened on the network to slow down the communications and the MSG completion took longer than 1 second, then you would start using up multiple buffers. If you incorporate the DN and ER bit in the conditional logic along with the Timer Done bit, this would also prevent multiple buffers from being used.

85. How can I send a message continuously? Every time you trigger a MSG, it sends the message once, trigger it again and send another message. So should I trigger a MSG every different second?See previous Question/Answer #7.

86. Can a MSG function be used on non-Allen-Bradley® devices that have Ethernet capability but support CIP Reads & Writes?Look for a future Webinar on using the CIP Generic option within the MSG instruction.

87. I've seen the Ethernet buffers lock up on PLC-5 controllers and the only way I’ve seen to reset it is to power down the controller. Is there some other way?If a controller’s communication port locks up and the only corrective solution is to cycle power, it is most likely due to the buffers being filed up. There is no solution on some of the older controllers outside of making sure that the buffers are properly managed (don’t use TMR Done bits or at least add in the DN and ER bits). On some controllers, FRN was enhanced to prevent communications from locking up and lastly some controllers had their ACL (ASCII Clear Buffers) instruction updated to

allow them to clear the buffers (SLC/MicroLogix).

88. In Logix, what is a Resource Unavailable error when executing a MSG instruction?A resource unavailable error is an indication that there are no buffers available to store the MSG data.

89. I have setup cascading messages (10) from ControlLogix to ten PLC-5 systems. Sometimes they error out. Why is this?I would need to know what the error code is on the MSG instruction.

90. Can you give an example or two of practical reasons for using messages?Many customers have applications that have exceeded their original design, and a 2nd processor has been incorporated to get past limitations of the original controller. Controller A needs to feed a signal to Controller B in order to perform some function. The MSG can be used to initiate a function in another controller.Many systems are designed to be controlled by multiple controllers and data from one system needs to be shared with another system.

91. Which processors support Modbus TCP?The only controller that natively supports Modbus TCP/IP is the MicroLogix 1400 controller.Please refer to Answer ID 470365 - PAC sample code for Modbus TCP Master and Slave for an open socket sample program that can be used with the newer Logix controllers that support sockets.Please refer to Answer ID 470690 - Open Sockets Support in ControlLogix and CompactLogix systems for a list of all the controllers that are compatible.

92. Shouldn't you check to see if the node is active before executing the instruction?Confirming first that a specific node is active can cut down on troubleshooting and can be done easily with a RSWho in RSLinx.

93. Is there any advantage to doing a Read vs a Write to move data?See previous Question/Answer #59.

94. You have shown Read MSG. Will other option be shown in future presentations?We are planning on offering more MSG Webinars in the future.

95. Can you pass data to a PowerFlex 700 drive from a SLC?I recommend contact the Drives technical support group for help on this question.

96. How do I update firmware on an older SLC 5/05?FRN kit 1747-DU501 is available for order from your local distributor and can be used to update the FRN of the SLC 5/05 controllers.

97. If a MSG instruction works properly most of the time, what would cause a controller to suddenly be non-responsive to a MSG Read for 10 or 15 seconds?If the MSG is working all of the time, we would expect the Done bit from each execution. Add programming to see if you are getting an Error and then see what the error code is. If there are no error codes, your controller could just be backed up from other communications in the buffer and needs to catch up.

98. Do we need to unlatch the MSG instruction Done bit after the bit is set?No, the MSG Done bit will reset on the next MSG trigger.

99. I set up a MSG instruction in ControlLogix to Read a PLC-5. It works in one ControlLogix controller but not in another ControlLogix. The only difference is processor model 1756-L61 rev 15.4 series A vs Series B. Is there a reason why series B would not work when it works in series A ControlLogix 1756-L61?I would recommend contacting ControlLogix technical support group for help with this question. I am not in the ControlLogix group to know their FRN that intimate.

100. Do you recommend using the message DN bit to trigger the next MSG command to avoid multiple calls?That is the mechanism used in our cascading example.

101. Can a Single Message be sent to multiple controllers simultaneously?Please refer to Answer ID 34299 - How do I send the same message to multiple controllers in RS5000 using the MSG command? for instructions on this.

102. Would you cover MSG usage for open socket from new 5730 series controllers?Open Sockets is another topic that should be covered in another future Webinar.

103. On the 1, 3, 2... communication path, does the ,2 indicate read-only to the controller or Read and Write?See previous Question/Answer #19.

104. Can you explain instance, attribute in the ControlLogix message?These terms are related to the CIP Generic option of the MSG instruction, which will be covered in a future Webinar. You could also see previous Question/Answer #24.

105. To execute a MSG read in a MicroLogix, reading from a ControlLogix/CompactLogix, do you need to map tags in the RSLogix 5000 program so that the MicroLogix can read it?See previous Question/Answer #42.

106. A 1756-dhrio module has 2 ports. How do you set the path for channel A or B?A 2 is always used to push out data on a module with one port. If a module has an additional port, a

3 would be used for the second port.

107. Can I send a User Defined Tag? What other tag types can I send? Strings?You can use a MSG instruction to Read/Write a User Defined Tag between two Logix controllers provided that the tag matches in the two controllers. Strings will work as well.

108. Can I use a MSG instruction to relay a User Defined Tag to another controller assuming it has the same UDT to receive it?You can use a MSG instruction to Read/Write a User Defined Tag between two Logix controllers provided that the tag matches in the two controllers.

109. With the cascade system, when a message block errors out, no other message block will be triggered. What is the solution to this?When MSG is triggered, it will result in either a Done or Error bit getting set. Use the Done along with an “OR” with the Error bit as well.

110. What is the default time for the ER bit, can this be changed for a slow responding network?The default timeout in the Logix MSG of 30 seconds is an enterable value in the SLC/MicroLogix/PLC controllers. Default in the SLC/MicroLogix/PLC is typically 5 seconds.

111. Can ControlLogix communicate over CAN bus? Also, is it possible to communicate with Siemens PLC or Drives?I am not aware of any CAN bus module (from Rockwell Automation or any EncompassTM Partner), but if one exists, then this should work. If you do a Google search, there are a couple of different third-party gateway devices that are available. The CIP Generic MSG option that was not covered in this basic Webinar would be the vehicle for third-party communications. Look for a future Webinar on CIP Generic MSG.

112. In Logix, PLC Family (ControlLogix or CompactLogix), can you access the read/write data directly from the message tag? For example, when using a MSG inside of an AOI, can the read data can be used inside that AOI without having to pass the tag that has been set in the Destination of the MSG instruction to the AOI?Look for a future Webinar to handle the advanced MSG concepts.

113. When doing a large system with Intra PLC (mixed families), what do you think of the idea of establishing a single register that is sent to all PLCs, which is a "clock" signal, and then using that "clock" signal to stagger comms amongst all the individual members?Good idea! This method would help cut down on incoming traffic to any one particular controller at any one point in time.

114. If I'm reading from another controller and the remote controller is offline, will I get the Done bit?

If the target processor is offline and or powered down, you will get the common error code 7h (SLC/MicroLogix/PLC) or 16#0001 with the extended error code of 16#0000_0204 (in the Logix style). However, if the controller is still powered up and in the program mode, it will respond to a MSG.

115. Is there a benefit of using MSG instructions from Logix to Logix vs using produced and consumed tags?See previous Question/Answer #12.

116. Does the mentioned path tech note cover PLC-5? Specifically, PLC-5 reading a ControlLogix via DH+/Ethernet bridge? Does that get overly complicated or is it just easier to make the ControlLogix write to the PLC-5?The tech note on paths only covers Logix style. When sending a remote type MSG from a PLC/SLC, there are several additional terms related to Remote Bridging Addresses, Remote Station Addresses, Remote Bridge Link ID and Remote Link types that needs to be understood that I did not cover in this basic Webinar. If you are unfamiliar with these terms, then using the Logix as the initiator may make better sense.

117. If I want a data collection database to receive events from a PLC, do you recommend using MSG instruction write to that database or should the database use OPC topic to get data?Either way is feasible and would be dependent on the application.

118. Correct the error and/or use a timer to bypass any error instruction or use the error bit as a OR to ensure the cascade continues

119. Did you set up the Map PLC/SLC Messages?You only need to configure PLC/SLC Mapping when non-Logix style controller needs to MSG to Logix style. See previous Question/Answer #42.

120. Is it possible to have a buffer overflow if too many messages are being sent without them being completed?In some controllers it is possible to completely lock up all communications if too many MSG’s have been triggered. See previous Question/Answer #87.

121. Is there a way to see the buffer or manages the buffer?See previous Question/Answer #25.

122. Please give more details on the Message Type. What to select when reading from a L43 controller?CIP Data Table is the method used to transfer data between to Logix controllers. See previous Question/Answer #45.

123. Do all of the messages to multiple devices have to be in one cascaded control? Or is it supported to have individual cascaded message controls?If you are using a cascaded method of programming MSGs, you are guaranteeing that a limited number of MSG buffers are in use at any one point in time. You can setup and use multiple cascaded methods provided that you do not pass the number of available buffers in the controller.

124. What error we can see to act if MSG buffer is full?The error that would occur is a 16#0001, extended error code 16#0004_0301.

125. A unique Message Type tag is created for each MSG instruction. When you click Apply in the dialog box, the MSG instruction configuration converts the path into string and writes it into the .Path element of the Message UDT. In this example, $01$01$12$11172.30.16.1:13101$00. What do these mean?

$01$01$12$11172.30.16.1:13101$00 would translate into a path of:1 (go to the backplane), 1 (go to slot 1), 2 (go out the port-most likely have an Ethernet module in slot 1), 172.30.16.1 (target IP address) :13101 (use Ethernet port address 13101)

126. Is there a guru on MSG blocks to contact?If you need help with a particular MSG instruction, feel free to contact Technical Support and start with the group that supports your initiating processor.

127. Can the RPI of a 1756-DNB cause an error code 16#0001? I am trying to communicate between a 1756-L62 Processor over a 1756-DNB Module, and a Scheider Electric ATV 32 VFD with a DeviceNet Com Card. Any suggestions?This is a specific question that should be directed to either the ControlLogix or Communications technical support group.