2v DC signal to operate an alarm

MisterBill2

Joined Jan 23, 2018
19,466
OK, so now we know that the meter is reading a signal from a variable speed drive system. And with the signal being zero to ten , probably correlating zero to whatever the max output of the drive is, it becomes clear that it would be very handy to have the scale calibrated in units that corresponding to what the output means. That is simple to do with a good process meter. I have done it and it is all done from the front panel of the meter, following instructions in it's manual.
So the TS needs to go to the Red Lion website and select process meters. And if they don't still have them Automation Direct should have them. Possibly cheaper, as well.
But there is a question as to why the drive current drops. For the screw drive in an injection molding machine, that would either be a blockage in the granular feed supply line or else the heaters have got the temperature excessively high. The motor drive current is a quite good indicator of the motor load, which depends on the viscosity and density of the plastic charge load.
 

MisterBill2

Joined Jan 23, 2018
19,466
From the TS comments, the drive is for a plastic injection molding machine in an industrial production environment. While it is possible to build an adequate enclosure to hold a homebrew electronic assembly, doing the job right would be quite a task. Injection molding production lines seldom win prizes for being a "gentle environment"' that delicate equipment would survive in.
 

MisterBill2

Joined Jan 23, 2018
19,466
I haven't had too much of a deep dive, but would something like this fit the bill:

https://au.element14.com/murata-pow...-c/dc-process-meter-5-digit-11-4mm/dp/3371926
Indeed, this process meter provides all of the functionality that is needed for the application. AND it can be calibrated to display actual amps based on the zero to ten volts input. It will require an external power supply but the current draw would not be much, and that same supply can power a small relay to provide an external isolated contact closure to fully automate the system, if that is required. I have not used the Murata brand controllers, but the specifications meet the requirements for this project.
 
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