DL06, Analog Card Grounding problems

Here's a little background on the project I'm working on.

For our senior project, a friend and I are using a DL-06 with a F0-4AD2DA card to track the position of a sawmill carriage. To track it, we're using a non-contact magnetic linear positioning sensor, and to move it, we're using a hydraulic proportioning valve with a current amplifier and a solenoid. We prototyped the entire project at my school, and we are now installing it at the sawmill.

The problem I'm having is that the Analog card isn't putting out any current. I've tried a different card, PLC, and terminal block, and none of those things seem to be the problem. The load impedence is well within the specs of the card, so I know that isn't the problem. The only thing I can think of at this point is that I'm having a grounding issue somewhere. All of my COMs are tied back to the COM on my 24V Rhino Power Supply, which is used to power the sensor and the current amplifier. Is there something obvious that I can look into to help solve this problem. I've never dealt with a grounding issue, so I don't know the things to check for.

With the power off, lift your wire on analog output #1 and measure the resistance between it and the "-" (common) side of your power supply.

It should measure no more than 300 ohms. I'm not sure that I believe that the lower limit is 0 ohms though...

Let us know what you read.

While you are at it, measure between your wire and the +24 vdc connection. Hopefully it reads infinity.

If your resistance readings fall between the specs of your module, then with the wire still off, connect a meter and a 300 ohm resistor in series between terminal #1 and "-" (or better yet, a resistor that matchs the impedance of your circuit - watch your watts, we don't want you cooking your fingers on your resistor).

Set your meter up for reading current and power up the circuit. Your meter should match what your program is outputting.

Of course you would want to leave the output wire going to your field device off for the test, this is just to make sure that your module is compliant.

If this isn't the case, then check to see if the outputs on the PLC are enabled, the 24 vdc power supply is working, the module is plugged in properly, the fuse isn't blown, etc. Does your 24 vdc power supply get pulled down by the load?

If you do get good readings, then it's time to start looking at your program.

Pictures of your setup would be nice...


Hope this helps.

mehret said:

Here's a little background on the project I'm working on.

For our senior project, a friend and I are using a DL-06 with a F0-4AD2DA card to track the position of a sawmill carriage. To track it, we're using a non-contact magnetic linear positioning sensor, and to move it, we're using a hydraulic proportioning valve with a current amplifier and a solenoid.

The problem I'm having is that the Analog card isn't putting out any current.

Click to expand...

My reading of the card specs is that the FO_4AD2DA is that it is a voltage combination card.

You say that the Analog card is not putting out any current,

I am wondering if you have 4 to 20mA devices out in the field trying to talk with a voltage card at your DL-06 PLC. ?

mehret said:

Here's a little background on the project I'm working on.

For our senior project, a friend and I are using a DL-06 with a F0-4AD2DA card to track the position of a sawmill carriage.

Click to expand...

Gil47 said:

My reading of the card specs is that the FO_4AD2DA is that it is a voltage combination card.

Click to expand...

The way I'm reading this the OP has not given us the correct or full information to allow us to give a good response.


.

mehret said:

The problem I'm having is that the Analog card isn't putting out any current.

Click to expand...

To save time. Can you list what you have done to trouble shoot your problem? Other than the list below.

mehret said:

I've tried a different card, PLC, and terminal block, and none of those things seem to be the problem.

Click to expand...

The problem has been solved, and the solution is too embarassing to post. It was a dumb rookie mistake.

mehret said:

The problem has been solved, and the solution is too embarassing to post. It was a dumb rookie mistake.

Click to expand...

Post your solution anyway. It will help the rest of us "dump rookies", I won't tell.

Just make sure you check the fuse in your meter.

OOOH my favourite, dumb rookie mistakes lets see most common is not using the meter in series with an analog signal although I've seen lots of experienced techs lose sight of what they are doing and forget that LOL

mehret said:

The problem has been solved, and the solution is too embarassing to post. It was a dumb rookie mistake.

Click to expand...

Er, you would have had your meter on a current setting when you tried to take a voltage reading, would you?