ML1500 HSC Woes...

Good day all,

I have an Allen Bradley Micrologix 1500 with an SMC stroke reading cylinder (CE1B20-75) hooked into HSC:0. It is using a phase differential sensor (CE1) made by Monosashi-Kun. I have never worked with the HSC's before so I thought I would start by building a test setup to ensure that I could read values from the cylinder, and go from there. The problem is that I have the processor in Run mode, the cylinder is connected as described in the literature, yet when I manually move the shaft back and forth, there is no change in the Accumulated value. I am looking directly at the function file, hoping to see change, but there is none. My sub-elements are set as follows -

PFN -9
UIE -1
FE -1
AS - 1
CE - 1
LPM- 1
HPM- 1
UFM- 1
OFM- 1
CD - 1
CU - 1
MOD- 6 (H)
HIP- 2147483647
LOP- -2147483648
OVF- 2147483647
UNF- -2147483647

Anything I haven't listed here is set to 0. I am looking at HSC0, which is where I have the sensor wired in.
Any thoughts as to what I'm doing wrong?

Cheers,

Mark

Mark,

Because you are moving it by hand (low speed), hook it to a normal input to see if you have it wired properly. If the regular input does not change, then you know there is a problem with your wiring.

The most likely cause is that you do not have power going to the cylinder sensor. It must have a voltage on one side, before it can close and send voltage to the MicroLogix PLC input (for either a High Speed or normal input).

Lancie1, thank you very much for your quick reply;

The output from the sensor, when metered, does fluctuate as the shaft is moved, but the reading is in mV. I have tried moving the cylinder with air pressure, but to the same effect. I have verified and re-verified the wiring, so I guess in an effort to eliminate the variables before I send the cylinder back to the manufacturer, my first concern is that I have the PLC set up properly.

Since my original post, I have verified that the Stroke reading cylinder does indeed work, by hooking it up to a stand alone Omron H7CR counter and observing the count as I move the shaft. I have tested the cylinder on BOTH Micrologix HSC inputs, as well as testing regular sensors on each input to ensure that there is an electrical connection; there is. I am able to observe the input signal in my program at each of the input points. I have also adjusted the input filter speed to these inputs...but to no avail.

Does anyone else have any suggestions?

Cheers,

Mark

Worsley said:

Good day all,

I have an Allen Bradley Micrologix 1500 with an SMC stroke reading cylinder (CE1B20-75) hooked into HSC:0. It is using a phase differential sensor (CE1) made by Monosashi-Kun. I have never worked with the HSC's before so I thought I would start by building a test setup to ensure that I could read values from the cylinder, and go from there. The problem is that I have the processor in Run mode, the cylinder is connected as described in the literature, yet when I manually move the shaft back and forth, there is no change in the Accumulated value. I am looking directly at the function file, hoping to see change, but there is none. My sub-elements are set as follows -

PFN -9
UIE -1
FE -1
AS - 1
CE - 1
LPM- 1
HPM- 1
UFM- 1
OFM- 1
CD - 1
CU - 1
MOD- 6 (H)
HIP- 2147483647
LOP- -2147483648
OVF- 2147483647
UNF- -2147483647

Anything I haven't listed here is set to 0. I am looking at HSC0, which is where I have the sensor wired in.
Any thoughts as to what I'm doing wrong?

Cheers,

Mark

Click to expand...

OK not sure if it helps but I have set PFN=3 and also all the ladder associated with the HSC0 is done in program file #3
I do not have any issues with the counter. I'm using an encoder to read position of a machine main drive and it has worked well.
My mode is set to 0 though MOD=0(h) since I need to count only one direction.
HIP=600 a 600ppr encoder
and LOP=0
Are you setting up the ladder in file #9?
Give it a shot.

Stab in the dark.
I have not currently got access to a ML1500 program using a high speed counter, so from memory I think you need to activate the HSC in the function file in order to see the accumulator value changing.

Gil47 : Thanks for your suggestion, but that was one of the first things I did. No matter, late last night we figured out the problem. It turns out that the encoder, being made in Japan, is an NPN device. Once we reconfigured the PLC, everything worked fine.

Thanks again for your help, all!

Let's hit the basics. Are the LEDs for Inputs 0 and 1, HSC0, or 4 and 5, HSC1 "flickering" as you move the rod?