Analog question

I have an Allen Bradley SLC500 PLC. Up to this point, I have only used Discrete input and output modules. I would like to add an Analog input and output module. The input module would be 1-5 volts and the output module would need to be 0-120 volts. Is there anything required of me to do other than putting the modules in and re-doing the configuration? DO I have to be concerned with PIDs or anything like that? Thanks

1. I don't think there is a 0-120V analog output card available for the SLC line.

2. Can you add modules to an existing PLC, sure. If you have a place to plug them in. If not you can always add additional racks.

3. Do you need PID loops, depends on the application.

4. Post a more detailed question, and you'll get a more detailed answer.


Ken

Greetings 401Bill,



and welcome to the forum ...



sounds like you’re adding the analog capability just for “learning” purposes ... and there’s NOTHING wrong with that ... but as my distinguished colleague Ken Moore has mentioned, the more we know about what you’re trying to accomplish, the more we can help ... and probably save you some money in the process ...



first of all, you probably don’t really have an “SLC-500” in the strictest sense of the word ... more likely you have an SLC-5/01, or SLC-5/02, or SLC-5/03, or SLC-5/04, or SLC-5/05 processor in your system ... it would be a good idea to use specific catalog numbers when you post ... sometimes the pieces of the puzzle just don’t “fit together” the way you might expect ...



based on what you’ve posted so far, you might be interested in the 1746-NIO4V module ... this one has two analog input channels AND two analog output channels both on the same module ... this would probably meet your training needs - and cost less than two separate modules (one for inputs - the other for outputs) ... here’s a link to an e-bay search that just turned up five hits ...



you mentioned a voltage output ... as Ken said, there is no 120 volt analog module available ... the most common voltage range is -10 to +10 VDC ... if you’re interested in a milliamp output instead, change the letter on the end of the model number from a “V” to an “I” ... basic idea: for the SLC platform, the analog input modules can be set up to handle EITHER current signals or voltage signals ... but the analog output modules can handle only one type or the other ... specifically, you have to buy the correct type of output module to begin with ...



you can read more about the most common types of SLC analog modules in this manual ...



good luck with your project ...

For a 0-120 Volt output, Carlo Gavazzi makes a compact little phase angle fired triac module (same size as a SSR puck) that you can use to convert a 4-20mA command to 0-120Volts (try NewarkInOne.com). These are fine for control of lighting and light resistive heating loads (20amp) where precise linearity is not needed. For larger loads you should use a regular SCR power controller.