Internet PLC Forum
General => Technical support => Topic started by: Bill on April 15, 2005, 07:15:47 AM
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First, thanks for a great product! I use your T100MD1616+ for all of my OEM products.
I have found that when installed correctly, this PLC functions flawlessly. I have one operating a communications system that has been functioning without incident for almost 2 years!
Now to my question. I would like to use a 0-5V reference voltage to control low speed cutoff for a valve
that applies a coating to a surface at high speeds. I have already used both high speed counter inputs for other measurement purposes leaving no available high speed inputs for frequency measurement. Can I use the analog input to measure 0-4096 based on input voltage to turn the valve off at some predefined voltage level, or should I consider another method to achieve the desired result? My project is on a very tight budget.
Thanks again for a versatile controller and great tech support.
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Thank you for your kind comments. We are happy to learn that the T100MD+ PLC works out well for your projects.
You certainly can use the analog input to measure a sensor output provided the sensor output voltage or current that falls in the range of the ADC inputs. E.g. for T100MD1616+ there are two channels of 0-1V analog inputs and two channels of 0-5V analog inputs. If your sensor output 4-20mA current you can still convert it to 1-5V using the a 250 Ohm resistor. Based on the input reading (0-4096) you can scale it to whatever reference value you desire using formula described in the "Frequently Asked Questions" board in this forum, as follow:
http://www.tri-plc.com/yabbse/index.php?board=2;action=display;threadid=349
You can then compare the scaled readings to the desired set values and decide to turn ON/OFF the valve. You can also use the PWM output to control variable opening for a proportional type valve (i.e. not ON/OFF only type).
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Thank you.