MSG from PLC5 to SLC

[Conor 4]

Hi all, I was wondering if someone can help me out. I am trying to send a message from a PLC5 to and SLC. My PLC's are as follows; PLC5/80 SLC 1747-L553C 5/05 Both of these PLC's are on ControlNet. I am not 100% sure how to find out the ControlNet address of the SLC. I think that if I can find this that I will be able to set-up a Multihop message. Can anyone throw any light on this. Thanks, Conor PS I have attached a doc with the settings. The ControlNet addresses are; PLC 5 address 3 SLC address 11 plc5_slc_message.doc Edited 11 Jan 2010 by Conor

[Ken Roach 194]

You do not need one Write and one Read; choose one. Do not use the Remote message type. This is for Data Highway Plus internetworks. ControlNet is considered a Local network. What exact model is in the SLC controller ? The 1747-SCNR does not accept "PCCC" messages but rather only access to the I/O table. You need a 1747-KFC15 to actually send messages to the SLC controller's data table.

[Conor 4]

Hi Ken, Why do I need to keep the Message types the same, if I am trying to write from one PLC, do I not read from the other. Conor

[Hardatwork 0]

You can use MSG instruction, just set up PLC5 type Write on the side you are writing from. For the MSG type to be configured as local we will assume that both PLC's are on the same network (nothing bridging one network to another). As ken said, you only need to set up a write to send the data - just make sure a valid address exists on the PLC you are writing to. Be warned that it will write over existing data on the side you are writing to! As for the SLC address, look in RSLinx (if know the name of the SLC). If you can get online to the SLC, you will find the address under "Channel Configuration". Best of luck...

[Conor 4]

Hi all, I have done some more work on this. I have a PLC 5 with an ethernet card in it. It is on the same network as the SLC (192.0.2.x). I have checked in the PLC 5, and all of the MG26 control blocks are used. I can't put the PLC 5 into program to create more, not at the moment anyway. My PLC's are as follows; PLC5/80 SLC 1747-L553C 5/05 Is there a way that I can send messages to the SLC from the PLC 5 via Ethernet without using the MG control block, or will I have to wait until I can add more? Thanks again, Conor

[Hardatwork 0]

you don't need to use the MG block. you can use any INT file, but a PLC5 WRITE can take up about 13 contiguous INT addresses.

[BobLfoot 302]

I've proven this fact in seveal previous posts so I won't belabor it here, but consider this a READ in the SLC will move data from the PLC 5 to the SLC {which is what you're saying you want} and consume about 33% less overhead and bandwidth than a write from the PLC5 to the SLC.

[Conor 4]

Thanks guys. So to clarify (for myself). I can use any Integer in PLC 5. Then I just do a Read in the SLC? Do I need to do a Read or a Write in the PLC 5? Conor

[Hardatwork 0]

If your READ instruction is in the SLC, you need no corresponding write in the PLC (it won't know about or care about the Read from the SLC). You don't by any chance normally work with Siemens PLC (for every 'Read' a 'Write' was more their thing...)!!

[Conor 4]

Thanks Hardatwork, Most of our stuff on site is Bradley, and I have only done limited work on Siemens. I thought that if you were doing a Write that you that you would need to do a Read. Sorry for bothering you again with another question. You mentioned that a PLC 5 Write can take upto 13 integer addresses. If I am not doing a Write now, I don't need to worry about this. I can just Read a specific Integer word from the PLC 5. Conor

[Hardatwork 0]

No Problems... What i meant about the 13 integers was using the INT file as the control address instead of the MG file. When you specify a Read in the SLC and you are not using a MG control file and just an INT control file instead; it takes up about 10 contiguous INT address. Talking about the size the Control it takes up is only a note, as you said you can't stop the process to increase the size of the existing MG file, so you might have another data file with enough space to get you out of a jam; that is all. Best of luck with it....

[Conor 4]

Hi, I have attached a new file, showing my latest try. In the SLC I have created a new Integer N19:0, and the last element being N19:204. I have checked the PLC 5 and I have the Integer N13:150 free. (N13:150 to N13:240 are not used) As you can see from the attachment, the error is; Target node cannot respond because it does not understand the parameters. Any thoughts? plc5_slc_message_1.doc Edited 13 Jan 2010 by Conor

[Hardatwork 0]

There are a couple of issues with your config (firstly i thought you were using Control Net, but there might be some things i'm not sure about): You are using N19:0 for the control block and giving it a lenght of 51, this would (i think reserve N19:0 to N19:50 in N19:0. I which case your Data Table address would start at N19:51. Essentially what the control block is doing is writing the configuration for the message instruction to a data file, if you try and read other variable on top of that then it wil change the configuration i.e. control block and data table address are different addresses. are you only trying to read 51 INT's from the PLC? You can reduce the size of the control block length for starters

[Conor 4]

Sorry for the misunderstanding. I was originally trying to send the messages across ControlNet, but it wasn't working. I then decided that because the SLC is on the Ethernet network 192.0.2.xxx and one of my PLC 5's is on the same network that I would send the messages this way instead. I don't want to Read 51 messages, but I can't seem to change the length of the control block. When I go into the Set-up Screen, I can change the length there, but this does not change when I go out of the Set-up Screen. I am probably doing something completely wrong!!!???

[Conor 4]

I got it working, finally. The error bit was latched in the message instruction. I put in a one second on/off bit to enable/disable the message and the error cleared (I read this in the help file, that the error doesn't reset until the message is disabled/enabled). I was then able to send a message between the two. Also, thanks Hardatwork. I see what you mean. The control block N19:0 to N19:51 are set up for comm's (I think). I used N19:60 to read the N13:150 Integer in the PLC 5. Thanks again for all your help. Conor.