adccommunitymod (AutomationDirect) asked a question.
reading analog value from remote location
Created Date: November 05,2002
Created By: awalinski
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Is it possible to read analog input values in DL250 register from a remote location e.g computer in head office in another city? What are the options? Is it possible to split analog signal and put it into two PLCs at the same time?
Created Date: November 05,2002
Created by: awalinski
Is it possible to read analog input values in DL250 register from a remote location e.g computer in head office in another city?
What are the options?
Is it possible to split analog signal and put it into two PLCs at the same time?
Created Date: November 05,2002
Created by: cj
First question: Yes, you can read values remotely. There are several different ways to do this. The capabilities of communications of your remote facility is typically the driving factor for the choice you make. If you have an internet connection through DSL or T1 at the remote location, you can put an ECOM card in your 205 base gather data pretty well this way. If you only have a phone line, you can use a modem to gather the info. ADC sells a good modem for this on the PLC side.
Second question: It depends upon the signal and the driving device but more often than not, no is the answer to this question. It is usually better to read the analog signal in to one PLC and send the value over to the other PLC via a shielded communication cable.
Created Date: November 05,2002
Created by: awalinski
Thanks! I knew about the modem, I am just a little weary of using US Robotics, which my company prefers because of a low price.
Did anyone used it with Koyo?
Created Date: November 05,2002
Created by: cj
I have used it in the past with some success but have had periodic problems. I know that ADC will not support any other manufacturers modems but the one they sell. They used to have a document describing how to use other modems like USR with their products but they removed it.
So...it's a gamble. Take the chance of having problems with the cheaper modems or go for the higher dollar one that you get support with. It's one of those budget-versus-reliability choices.
I myself am inclined to put the ADC modem on the PLC and use a more standard modem on the PC side. I usually buy a spare one of each for troubleshooting. Modem connections are one of those areas in which you may spend 5 minutes getting it to work or 5 months...
Created Date: November 07,2002
Created by: marksji
Is the analog signal voltage or current? If its current its simple to daisy chain it through several analog inputs, just be sure your device can drive the total load (input impedance + wire resistance).
As for the modem, I wouldn't even consider running a non-industrial modem on the remote end of a PLC link. To much hassle to fly half way accross the world to replace it.