Best approach to wireless DH+ (~1000M)

[ptine]

Hey guys thanks for the help on the other posts I really appreciate it. Saves tons of time and kinda cool interacting this way. At work here we have 4 plc5/30 and 4 plc5/40 on DH+ using blue hose. The site is spread out (~1000 metre radius max) and we have only 2 computers linked to the DH+. One in our shop and the other in a not so centrally located substation. The problem is that we usually need a guy out in the field and a fellow in front of a screen to verify and troubleshoot various problems. I am being told that if I put together a proposal that our supervisor will try to get the powers that be to purchase a laptop with the appropriate hardware & software that is needed to enable us to have a wireless laptop that we can leave in a truck. Any and all ideas would be greatly appreciated. Thanks.

 

[rsdoran]

A simple method would be to setup a wireless Ethernet system for your computers. The distances involved means you may need range extenders but take the time to look at it.
http://en.wikipedia.org/wiki/IEEE_802.11

The laptop, with this method, could use a program like CloseUp or Norton PC Anywhere; which eliminates having to add RSLogix and associated licensing.
http://www.norton.com/home_homeoffice/products/overview.jsp?pcid=pf&pvid=pca12

Unless you have some really harsh conditions you may not need industrial grade either, look at D-Link and Linksys:
http://www.dlink.com/products/?pid=357

http://www.dlink.com/products/?sec=0&pid=6

http://www.linksys.com/

 

[JesperMP]

One part of the job is how to layout the wireless ethernet.
The other part is how to get 8 PLC5 CPU's on ethernet.

The radical but also expensive solution would be to install 1785-ENET modules in each CPU.
*

Alternatively an 1769-NET-ENI attached to the DF1 port on each CPU could also do the job.
*

And these guys have gateways for DH485/Ethernet and DH+/Ethernet:
http://www.protocolconverter.com/products/DL4500.htm
They have been mentioned a number of times in several threads, but I have never seen a list price for them. I would like to know.

Or you can also setup a ControlLogix chassis with a DHRIO module and an ENBT module.

Or, as you allready have 2 local PCs connected to DH+, they could act as gateways to Ethernet. You would need RSLinx Gateway to do that.

Or, you could have RSLogix on one of the 2 local PCs, then you could use remote control software to program or troubleshoot remotely. I think this is also what rsdoran suggest. But you would need an RSLogix license on the PC.

*: These two solutions doesnt burden the DH+ network. With 8 PLC5s + 2 PCs allready on the same network (probably running at 57.6k), you should worry about not putting too much extra traffic on the network.

 

[rsdoran]

From the original post I assumed both PC's already had the necessary software for working with the PLC's.

801.11g basically is limited to 100m but the draft technology for 802.11n supposedly can range up to 500m at faster rates. The problem is the 802.11n products being made now may not be compatible with products when 802.11n technology is finalized.

My thoughts if using 802.11g technology would require 3 PC adapters, 1 router, and possibly 4 range extenders. You may need more range extenders but it would depend on actual distances for the machinery and line of sight issues. What would be great is if you have or could run physical wiring for ENET then you could just use some access points, which may lower costs.

The real cost would be the laptop, it would not need to be the latest and greatest but would probably need to be a "Toughbook" type designed for hard use.

Basic cost estimate:
Wireless components $1000
Software $300

WE, me included, jumped on the WIRELESS and/or Ethernet aspect but in reality you may not need it, you have an existing network. You could obtain a laptop and just add RSLogix and Linx to it then be able to access any PLC through DH+ or serial as needed. There were not enough specific details for the need of wireless to say if it would be more appropriate or not. I do not know enough details but you may be able to remove the license from the remote station since the laptop will be mobile and available if needed, this could save costs of another license.

IF the laptop is just going to be used for troubleshooting and not making changes to programs then I thought you may be able to use RSLadder but I can not find if it is still available.

I would make sure the laptop has a built in serial port just in case.

 

[JesperMP]

From the original post:

The problem is that we usually need a guy out in the field and a fellow in front of a screen to verify and troubleshoot various problems.

So it looks like that they are after being able to access the program of any of the CPUs from basically anywhere, not just next to one of the PLCs.
So I think that wireless ethernet is the only realistic solution.

edit: Actually it does not say in the original post if they have RSLogix on the local PCs. If they do have, then that obviously should be weighed in.

 

[rsdoran]

From the original post:
So it looks like that they are after being able to access the program of any of the CPUs from basically anywhere, not just next to one of the PLCs.
So I think that wireless ethernet is the only realistic solution.

edit: Actually it does not say in the original post if they have RSLogix on the local PCs. If they do have, then that obviously should be weighed in.

Not enough details were given BUT..I assumed the 2 PC's had RSLogix and could connect to ANY PLC on the DH+ network. This meant that when troubleshooting someone had to go to the shop computer and go online with the specific PLC involved while someone on plant floor was in radio communication doing the physical work. I have been thar done that...

I mentioned the last part about installing RSL on the laptop because if troubleshooting a specific system then they would need to be at the system anyway.

I backed up on wireless ENET because I am not sure it is necessary in this situation. It appears they just need to be able to access the program(s) for a particular system while working at the system. The direct connect method would be more secure and less involved then going wireless.

 

[Ken Moore]

There are industrial wireless access points with much greater range than the home use ones. If you have a central location that you could mount an antenna up high on, you could cover the entire site with one point. The draw back is that most of the industrial wireless access points are only 802.11b.

Here's a link to one source: LINK


You would still need some type of DH+ / Ethernet bridge.

 

[Christoph]

Here in our plant the entire facility is covered by wireless E-net.
Our laptops are wireless. 75% of our PLC's are E-net the rest are DH+
We have a controllogix gateway bridging the 2 together. I can access
any system, anywhere. This is the greatest. But keep your PLC Enet
seperate from normal plant E-net traffic.

 

[JesperMP]

This meant that when troubleshooting someone had to go to the shop computer and go online with the specific PLC involved while someone on plant floor was in radio communication doing the physical work.

Yes I aggree. It is the same that ptine describes in the original post, and then also say that having to use 2 guys is a "problem". So I take that the goal of the original post is to figure out how to allow access to any CPU from anywhere thus allowing only 1 guy to do the job.

 

[ptine]

Morning all. Just to clarify my earlier post. The goal is to be able to go out in the field and be able to troubleshoot equipment without having to be in contact with someone back at a terminal via radio. Both PCs have RSlinx. What the real issue is being able to pinpoint the issue and quickly be able to troubleshoot the suspected device. Being able to watch a limit$ transition for example can be invaluable and a real time saver in the troublshooting process. We don't always need the wireless but when you do we find yourself thinking that if you did have a wireless connection/laptop linked to the DH+ you would have been able to have gotten the equipment back up and running a lot faster. Thanks again

 

[allscott]

Just wanted to mention that with a PCMK in a laptop you can go online to any of the PLC's on the Floor and access all of the PLC's on the network (provided channel 1 is set up as DH+ on the PLC's).

I don't know if this would put you as close as you want to the equipment or not.

Ron's wireless solution is actually cheaper than the cost of a new PCMK but they are available on Ebay for less.

I just wanted to make sure you were aware of this option.

Laying on your back with a limit switch apart and a laptop on your knees and being able to trigger it and see it work is pretty cool though. I will push for wireless capability here when I get the rest of the mess here straightened out.