Slaney

It was a wiring issue as Simon suggested. It appears everything is working now. I am registering counts on a change of state. I also was able to get the HSC to Freq function to work, so I have frequency in 0.01Hz increments to convert to RPM. I don't have the motor available at the moment to test it on that, but I counted the number of times I manually activated the switch over 1 min. and the rpm reading was reasonably close. I'm sure that improves with more time and consistent pulses. Thanks everyone for the assistance. Now I just need temperature and air volume control on a hot air blower, to set up some cycles to open an close a solenoid for a spray nozzle, and a counter and I will be in business.

Looks like I have some things to check and try. I'll let you know what I figure out.

Gentlemen, thank you for the responses. Ausman does have the situation correct. I am getting counts and the 190Hz frequency unless the sensor is close enough to a target to open. I get some lower, but incorrect frequency when the motor is running. I’m thinking the problem is that we are targeting a protrusion from the coupling with a normally closed sensor, so as I think Ausman is eluding to, there is always a signal except for the brief moment the protrusion passes. We probably need a normally open sensor or move the current sensor closer so it is open and target a negative feature. Does that sound reasonable, or am I not understanding? To answer Joe’s question, the 0-10V pot is part of a purchased control panel that I guess would be considered a driver. We did have to cut the 9 wire cord that connects to the motor to put in a through wall connector. I have no idea if it’s possible, but if it is, I imagine we could isolate the correct wires to pull into an analog input. I’m a materials engineer (or metallurgist) and my colleague is a welding engineer, so I’ll have to do some research on that.

A colleague and I are in the process of putting together a test rig that is controlled by a Samba 7 (RA22 model). We have pretty much zero experience using PLCs, so we are putting things together in baby steps (and this might be the first of many posts). The first road block we have hit is getting the HSC to work. The rig has a motor on it that is separately controlled, but has a 0-100% pot on it and there are some people here that haven't met a knob yet that they didn't turn. We would like to have the PLC display the RPM to make the tests more repeatable. The motor has a max speed of ~1850 RPM and we currently have a feature on the coupling that we can target off of to give us 1 count/rev. The first question would be, is the HSC the best route and should we try to add more features to get the counts/rev higher? We have an inductive prox switch laying around (Pepperl Fuchs 3RG4021-0GA33-PF, 3wire, 24V, NPN, NC). We have the NPN jumper selected and have the black wire to I0, the blue to 0V and brown to common. Second question is, is that correct? The LED on the switch is lit and does go off when the tip is touched off of metal. Third question is, is a NC switch able to be used for this or do I need a NO switch? At the moment, I have the hardware configuration set for High Speed Input with a simple HSC and the second line is set for Frequency Measurement 1000msec. The MI for the counter appears to be counting when the switch is closed and stops when it is open. The MI for the frequency goes to a max of 190 when closed and 0 when open. Is there more that I need to do to get the real frequency or is this due to the NC switch? I also tried following the HSC to Freq example in the Help, but that didn't seem to work either. Any help would be much appreciated