ControLogix Analog mA Value

Good Morning,

First time posting here.

How can I get the mV, V, mA value coming into a 1756-IF6I card?

I understand these are converted to counts, but I need a way send the value from the sensor (mA, mV or volts) to an HMI. So on the HMI we will have the scaled value, and the actual reading from the sensor.

Can this be done?

Thanks,

Burch

wellcome

your reference

Thanks for that information. I looked through it, and it seems mostly related to scaling.

What I looking for is a way to get the value from the device to the HMI.

For example, if 15.0 mA is scaled to 125PSI within the PLC, I need to send the value of 15.0 mA to the HMI along with the scaled value of 125PSI.

Thanks,

Burch

First, why? Is it to allow easier loop checks for techs or something?
Is the scaling done in the card configuration or a compute block?
In past AB PLCs the counts would be stup to equal the MA value x100 or so. 4000 = 4.000 ma and so on
Look at how it is scaled and you might need to do a reverse compute from the PV in eng. units to MA.

Numeric Display

HMI Tag from Controller Tags,

and from PID/PIDE block,

Burch said:

Good Morning,

First time posting here.

How can I get the mV, V, mA value coming into a 1756-IF6I card?

I understand these are converted to counts, but I need a way send the value from the sensor (mA, mV or volts) to an HMI. So on the HMI we will have the scaled value, and the actual reading from the sensor.

Can this be done?

Thanks,

Burch

Click to expand...

The IF6I card, when inserted into the I/O configuration with Comm Format "Float Data", does on-board scaling.

By default, the card configuration is for a -10 to +10 Volts input, and the scaling values are....

-10V signal to give -10.000 engineering units
+10V signal to give +10.000 engineering units

Most people adjust these scaling parameters to match the engineering units of the sensor range, so that the data that appears in the Input tag is directly scaled to engineering units, and the controller does not have to do any scaling.

To calculate the input signal that is applied to the channels, you will have to back-calculate the signal from the scaling parameters (effectively "un-doing" what the card has done.

An SCP (Scale With Parameters) instruction would be most suited, but unfortunately, Logix5000 does not have the SCP instruction, but there is a sample SCP Add-On Instruction that can be used in version 16 and above.

All of the info you need is in the Location:Slot:C tag that is sent to the module to configure it.

It is only scaling.
Once the value has been digitized, you can display it however many ways you want to. Take the number, and scale it 30 different ways to 30 different tags and display them all.

There is no specific "Actual Value In Volts or milliamps" that comes from the input module.