adccommunitymod (AutomationDirect) asked a question.
one 0-10v sensor to two plcs
Created Date: September 06,2011
Created By: nhermanson
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I have an grain dryer that has a moisture sensor with a 0-10v output going to an existing plc. I'm looking for options to input the sensor's reading into a seperate click plc. Is it as simple as jumping the signal line from the analog input of the existing plc to a signal conditioner to the plc? Or do I need to put in a specific splitter to split the signal two ways. Thanks Nick
Created Date: September 06,2011
Created by: nhermanson
I have an grain dryer that has a moisture sensor with a 0-10v output going to an existing plc. I'm looking for options to input the sensor's reading into a seperate click plc. Is it as simple as jumping the signal line from the analog input of the existing plc to a signal conditioner to the plc? Or do I need to put in a specific splitter to split the signal two ways.
Thanks
Nick
Created Date: September 06,2011
Created by: johnaden
If I read your message correctly, you would go from the existing PLC through a signal conditioner, then to the Click? If DC comm is at same potential, I don't think the signal conditioner would be necessary. For my interest, what grain moisture sensor are you interfacing to?
Created Date: September 06,2011
Created by: nhermanson
It is a NECO grain dryer that is using a dryer master moisture monitoring system. The moisture sensor is wired straight to a voltage input on a schnieder plc to control the dryer.
I have a productivity 3000 system that is running the rest of the grain setup that I will be remotely monitoring in the field through my ipad. I don't think that I will get remote access to the schnieder plc, so my thought was to just throw a click in the dryer plc cabinet to talk to my c-more screen to monitor the moisture levels and use current switches on the motors to make sure everything is running. I won't be able to control the dryer, but at least see what is happening.
So basically I just want to branch off the 10v signal from the moisture sensor and send it to a click, but I will need the conditioner to drop it down to 0-5.
Created Date: September 06,2011
Created by: Bob S BN
Not sure what schnieder plc you have, but does it have a open comm port that you could hook to the P3 on a comm port and perhaps read that data address via modbus?
I'd hate to see you throw in a Click and a conditioner just to capture that one number,
Just a thought,
Created Date: September 06,2011
Created by: Tom Jenkins
In theory you can run as many voltage signals in parallel as you want. However, there are some things to watch for. Bernie's cautions about EMI/RFI are important. You have to make sure that you don't have problems mixing commons at different ground potentials. You also have to make sure that the total resistance is above the minimum allowed by the transmitter.
The safe way is to put a signal isolator in the dryer panel, assuming you can't just read over a comm link.
Created Date: September 06,2011
Created by: bcarlton
If the Click PLC is very close to the other and shares the same DC common then it should not be a problem. Be sure not to cross any high voltage wires while making the connection. Observer the resultant signal carefully. If there is any droop or noise induced the get the isolator.
Created Date: September 06,2011
Created by: nhermanson
I 've considered something along that route. The issue is that it is a stand alone control package that I don't have programming access to. I haven't talked to the engineer to see if he would set something up for me yet, but I'm not holding my breath on that route. I also plan on reading 6 current switches and the rpm of a shaft as well, so the click would be more than just one sensor.