Can anyone tell me what the symbol for an Analog to Digital card is for an AB RSX PLC progamming? I know for example that a Normally Open push button that is wired to the common and to the input buss, say slot 2 bit 12, I:2/12 would be the symbol on the ladder logic for that, an A to D card in say the same slot (slot 2), what would you type for the designator. I know that a normal A to D card usually has 4 channels at 1 to 10 volts for the analog input signal which the A to D card then converts to a binary number the PLC can interact with the program to fire the outputs accordingly. Please can anyone give me help on this.
Need Help Please.
- Thread starter 7romero1
- Start date
Ken Roach
Lifetime Supporting Member + Moderator
Welcome to the Forum !
In general, A-B analog modules present the analog value as a number of integer 'counts' in an I/O data table file that is related to the slot position of the module.
Are you using a MicroLogix or a modular SLC-500 controller ? Do you have an exact analog module part number in mind ?
The range of the integer values depends on the exact module and configuration. Some modules let you configure the data as raw counts, scaled-for-PID counts, or engineering units.
As one example, a 1746-NI4 module in Slot 2 would present its data as:
I:2.0 = Channel 1 Analog Input Value
I:2.1 = Channel 2 Analog Input Value
I:2.2 = Channel 3 Analog Input Value
I:2.3 = Channel 4 Analog Input Value
Because the 1746-NI4 uses a 16-bit A/D converter, the value would be between -32768 and +32767 for an analog input voltage of -10 to +10 V DC.
In general, A-B analog modules present the analog value as a number of integer 'counts' in an I/O data table file that is related to the slot position of the module.
Are you using a MicroLogix or a modular SLC-500 controller ? Do you have an exact analog module part number in mind ?
The range of the integer values depends on the exact module and configuration. Some modules let you configure the data as raw counts, scaled-for-PID counts, or engineering units.
As one example, a 1746-NI4 module in Slot 2 would present its data as:
I:2.0 = Channel 1 Analog Input Value
I:2.1 = Channel 2 Analog Input Value
I:2.2 = Channel 3 Analog Input Value
I:2.3 = Channel 4 Analog Input Value
Because the 1746-NI4 uses a 16-bit A/D converter, the value would be between -32768 and +32767 for an analog input voltage of -10 to +10 V DC.
Thank you for writing me back, I under stand some of what you said, I dont have any moduel in front of me, I have written very simple PLC programs before, that use timers/counters/Input buss bits (devices like switches etc.) and internal relays, and I know what the bit word for example a TON T4:15 has 16 bits (the bit word) and bitts 13, 14, 15 are reserved for the EN, DN and TT. but if I had the A to D card that you are talking about that uses counts from -32768 to +32767 and has the -10 to +10v and I put it into say slot 2, and I created a rung, what would I put on that rung to designate that A to D card in the program/PLC? If it is an input I understant that it will be wired to an input devise like a pressure transducer or something that puts out an analog voltage (signal) to the slot 2 channel say 3. please can you help me,
Ken Roach
Lifetime Supporting Member + Moderator
Generally you use GRT, LES, or LIM instructions to address an analog value in ladder logic.
Thank you again, I under stand the comparative funtcions greater than, less than etc. Thank you.
I worked out in Mosses Lake for 11 months in 2007 for the IBEW (union electrician local 665 out of Lansing MI. That was the first and only time that I had been to Washington state, I was supprized at how hot it was, and also desert like terrain, I had to drive to Seattle to the Union Hall to get the work referal, it was snowing up I-90 going up and down the Casscade Mts. white knuckles on the wheel there and back. Thank you again for your help,
I worked out in Mosses Lake for 11 months in 2007 for the IBEW (union electrician local 665 out of Lansing MI. That was the first and only time that I had been to Washington state, I was supprized at how hot it was, and also desert like terrain, I had to drive to Seattle to the Union Hall to get the work referal, it was snowing up I-90 going up and down the Casscade Mts. white knuckles on the wheel there and back. Thank you again for your help,
bernie_carlton
Lifetime Supporting Member + Moderator
The Cascade mountains in Washington definately divide the state into two very different parts both climatically and politically. The 'left' and 'right' terms applied to liberals and conservatives have a very literal meaning in our state.
Hello, I understand what you mean Right and Left, I didnt know that untill you explained it to me, in Michigan we have Uppers (Youpers) and Lowpers for the U.P and L.P., also are you anywhere near Waxahatchie, I dont know if I am spelling it write.
Mr. Roach, thank you for you answers, I think that I understand now, if I have an A to D card in a certain slot and I put a comparitive function on a rung say greater than and that function has to have 2 sources to compare in order to be true or false, you make the source that is being compared to a fixed number/value and when the X-ducer analog input signal gets greater than the set value the greater than function fires true or has logical continuity. Thank you again
bernie_carlton
Lifetime Supporting Member + Moderator
If you mean Wenatchee it is Northwest from Moses Lake. Yakima, where I live, is Southwest from Moses Lake.
Here's a map
Last edited:
Firejo
Member
If you’re talking about how to pronounce Wenatchee, you are mistaken. It’s pronounced just like it’s spelled wen-at-chee
also you can scale that analog value to a useable value to compare to. lets say you have a 0-100psi pressure anolog input. well then you could scale your 0-32767 to be 0-100 and then compare when say you want something to shutdown at 60psi. much easier than doing the math for the raw data for a setpoint and easier for everyone else later to make changes.
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