To much cereal....I mean serial

stooperbike · Jan 19, 2005

I have an application were I have 12 instruments with serial ports and need to log some of the data from each instrument. Of course none of the instruments have 4-20’s so my only hope is to take data from each serial port. My thought was to take 12 serial to Ethernet converters, make a network and bring that data into a PLC. This would assume I could get or write a driver for the data. Has anyone run into this situation before? I mean lots of serial data and no were to put it. Also…if someone walked around a plant and cut all the serial communication lines would that make them a serial killer? sorry to those whom I’ve told that to.

JesperMP · Jan 19, 2005

What kind of PLC are you using ?

Siemens has small serial interfaces that installs in the ET200S "racks" on Profibus DP.
6ES7 138-4DF00-0AB0 speaks ASCII on RS232/RS422/RS485 with an interface of 4 bytes i/o.
You could attach this to any PLC system that speaks Profibus DP.

Edit:
Oh, by the way, there are also interfaces that speaks "Modbus" or "USS" if that is a better solution for ya.

BigAl · Jan 19, 2005

Serial problems

I can remember working on a few applications some years ago, that required many serial devices which had to communicate to a PLC. We utilized some serial PCI cards from byterunner.com. The cards we used took up one PCI slot,but had 8 serial ports each. We also used a software package called Winwedge, which worked great for setting up each port. In our instance we used a Wonderware package as the HMI, which you may not need depending on your application. If you need more information, let me know.

Big Al.

Ken Roach · Jan 19, 2005

My first approach would be to use standalone DeviceNet/RS232 converters, if I had an A-B or Omron control system and if the devices were nearby.

If they are widely spread out, you might consider Ethernet/Serial converters. You can use a module that goes into an Ethernet-connected I/O system (like ET200s or POINT I/O) or you could try a Port Server of some kind.

Does this data need to be in the PLC, or just in the datalogging software ? If it's software only, I think the idea of a "wedge" to DDE/OPC is the best.

alphageek · Jan 19, 2005

Is this RS-232 or some multi-drop protocol (RS-422, RS-485)? If the latter, it shouldn't be too hard to accomplish with one port. If the former, I'd suggest a multi port PC card mentioned by BigAl and a fairly simple VB app.

Andybr · Jan 20, 2005

We do this succesfully using DeviceNet modules as suggested by Ken above. Provided that you know exactly what you need on the RS232 side (Hardware settings and protocol) the system should be reliable and easy to set up. Our preferred module is Escort Memory Systems CM11 which is quite expensive but bombproof and does not need to be mounted in a panel. An additional advantage of this approach is that it greatly simplifies the PLC code required to handle the comms. Similar modules are available for Profibus etc.

Jiri Toman · Jan 20, 2005

The best solution to this problem is offered by Wago. Use one of their newer processors, they can be set up to talk either Modbus/TCP
or EtherNet/IP so they can pretty much communicate data to any
modern PLC. They have ASCII module which will allow you to
bring in the data in generic ASCII mode and then massage it inside the
processor before you send it to another PLC. Of course you could get an OPC driver for their processor and bring it into a PC.
One big plus is that Wago is very inexpensive.

stooperbike · Jan 20, 2005

Thanks for info, I am feeling like I dont have a good handle of what this customer wants. This is a data logging operation only, no control so going strait into a PC would be the way. As far as I know there is not a multi-drop protocal on these intruments.

JesperMP · Jan 20, 2005

What are the instruments (make and type) ?
What is the datalogging software ?

stooperbike · Jan 20, 2005

the instrument is YSI model 5100. http://www.ysi.com/environmental.htm
and as far as data logging software.. ihave no idea what to use. I am leaning towards the National instruments but I am nervous since I do not have alot of experiance with it. I am also worried because I am sure we will have to write some kind of driver interface for this thing. The manual for the device shows all the ASCII stuff to create a driver but........ I am still nervous. NI has a sixteen port serial interface card that will go into a PC anyone know anything about that? Thanks so much for the help.

JesperMP · Jan 20, 2005

I would contact YSI and ask them if their software BODANALYST can connect to several 5100 instrumnts at the same time, if it can accept up to 16 COM ports, and if it can run on anything higher than Win 95 or Win 98 (as stated in the specs).

Explain to them what you want to achieve, and ask them if it is possible.

To much cereal....I mean serial

stooperbike

Member

JesperMP

Lifetime Supporting Member + Moderator

BigAl

Lifetime Supporting Member

Ken Roach

Lifetime Supporting Member + Moderator

alphageek

Member

Andybr

Member

Jiri Toman

Member

stooperbike

Member

JesperMP

Lifetime Supporting Member + Moderator

stooperbike

Member

JesperMP

Lifetime Supporting Member + Moderator

Similar Topics