RiverAmy

I have conflicting mapping data for the 1336 plus 2 drive 240A 460V. I have 6 bytes in and 4 bytes out, but when i called allen bradley, he told me that the pad words are nothing. that part is ok, what's conflicting i read in the manual that the first word is a pad and he said the second word is a pad...Is there any place that i can find the correct mapping for the device? I clicked on the help in RSNetWorx's but it didn't have any information at this time. what i'm trying to do is set up a user defined data type and i don't know which words are good and which words are pads. Thanks for your help

Hello, I'm trying to control some VFD's (Variable frequency drives) using a PID instruction in my RSLogixs5000. I have an Actual Flow Rate (feed back) and a Set Point. the problem I'm having...I'm not sure how to send the output of the PID to my VFD's. I'm communicating with DeviceNet (1756-DNB). Do I need to Covert my answer then output it to the VFD's. For example, I know my pump capacity is 0 to 1200 gpm. Do I need to convert that to another number like FOR EXAMPLE, 3277 to 16384? I had a card that required that once for a 4 to 20mA signal. Oh, I'm using PowerFlex 700 (if that helps). I'm using a scheduled routine for every 250 ms. I have a MOV instruction that takes my requested Set Point to VFD.SP then i have the PID instruction following my Process Variable = Actual Flow Rate (my feedback) and the Control Variable = is a newtag I call Speed ....Now I'm stuck If you need more info. just let me know Thanks for your help, Amy

I think most of my problems are coming from the ProSoft card...I can't test this theory till i get the prosoft card to quit asking the same question over and over...i just got my equipment a couple of days ago and i started testing it and today i realized my problem... the card is asking the same question (the first one sent) over and over instead of asking the next step...i didn't know that was my problem till i looked at what the ML was receiving. i'm not sure how to fix this yet. I'll try what you are telling me when i get this fixed...thanks so much for you help. Amy

Here are the steps that i want to do... step 1 Send Display text to ML "Enter Tank" step 2 Send Display text to ML " " (this is just a blank line) step 3 Send Display text to ML "Tank 9" step 4 Send Display text to ML "Tank 12" step 5 Send Display text to ML "Tank 14" step 6 Send a command that allows the operator to choose which tank they want to pump from step 7 Send a command that reads the keypad (so i know which tank the operator has chosen) step 8 put a timer for 90 seconds (this is just how long it takes to go to the enter batch screen) step 9 Send a command to authorize the ML. see note* step 10 (here is my problem) send a command to check the status over and over till i see an input returned. also, i'm checking for the Note sections below* oh, i forgot it takes about 250 mSeconds to get the response back from the ML device. I'm thinking that i will need more timers. see note * send a RQ command to Request flow rate of chosen ML. then add anyother ML that are on the chosen pump. I will control the VFDs according to the info i get, i will use the Read Keypad to know which tank they want to pump from then when it's started (input true) i will add 400 gpm to the set point of a PID (inside PLC). and the same for when the stop is ture i will subtract teh 400 gpm from the PID. I request the flow rate from the MLs so that i know how much flow i'm sending and what i should be sending so i can adjust the PID too. all the following info. comes from that status command of the ML... * Note. i will only start the pump if the authorize command is true and the input (start) is true. I will only do the authorize command if input is not true, keypad data pending is not true and tansaction and batch done are not true. i will stop the pump only if i have authorize true, input not true, and if one of these are true...(transaction and batch done, or transaction in progress and batch done, or keypad data pending. I hope i'm explaining what i'm doing o.k. thanks for all the help Amy

Sorry about that, #1& #2... I have 9 Microload devices w/ each ML controlling the flow to one railcar. i have three tanks that i can pump from. each of the tanks have their own VFD( three pumps). all the tanks are on the same line suppling product to the railcars. #3...the plc will control the VFDs, but the operator at the railcar will enter which pump they want and they will enter a batch and then press start. when it is started i want to keep checking the status so that i can see when that input (start button) has been pressed by the operator. So, i can then start my pump for that tank the operator has just picked. #4...yes the PLC will control the VFDs depending on how many ML are pumping from the chosen pump. so if two operators (two ML) have chosen the first tank then i will adjust the speed of that pump. i do request the flow rate of the ML so that i know how much flow is going to the railcars. each ML will be set for 400 gpm.

I want to ask a command and get responses (etc. status) over in over in one scan but after i have asked a couple of other commands first (to the ML). I have the gsc card set up to be continuous. i think maybe i'm asking my question wrong.

Yes, it is the MicroLoad.net device. i'm testing on a 1756-L61 series A. the proSoft card is the MVI56-GSC. I'm testing over RS-232,but I will use RS-485 in the field. Mellis, I'm just controlling three pumps depending on the Meter's request for flow. I don't control the MicroLoad.net (Smith Meter) which is a controller that keeps the flow at a set point. for example all my MicroLoads will be set for 400 GPM (gallon per minute). My problem I'm having... is that i need to know the status of the MicroLoad.net over and over before i can do other steps. For example, I want to start the pump, but i need to keep checking the status of the ML to know when i see an output (the operator has started the batch) then i can start the chosen pump (the operator choose) and depending on how many ML are pumping from that pump then i can adjust the speed of the pump. I have programmed it like normal I/O saying send a question then wait for a response then do the next question only after you get a response from the previous question. i'm just stuck on the status question. i need to check it at all times. in my program i'm doing CMP if the response is this then do required task. You guys were right about the VB and C++, i was programming like that and realized that is not going to work. I'm not good with PLC's at all, but as long as my boss is being really nice about me learning... I won't give up. i think i will really like this when i get the hang of it. thank you for taking the time to help me. Amy

Because, I need to know for example... if i have an input and it is authorized then start pump, how i know this is i send a command to ask the device i'm communicating with over and over again until i see what i want...like the input. another exmaple, if i don't have have input, transaction and batch done then authorize the device i'm communicating with. in other words, I need to know what the operator had enter and when so i can control the pump or whatever they need. did that help?

I'm not sure how to ask my question, but I will try. I have a device that I'm communicating with and I'm asking a command and I want a response, but the problem is... I want to ask the command and get responses over and over before the next scan. For example, I am asking a device what's your status, then it will send me a response. in order to command my next steps, I need multiple responses about the status (before the next scan) Does this make any since? I'm using a ProSoft card and I understand how to get and recieve data. Just not over and over in one scan. thank you, Amy

Hi, I'm having some trouble...I was called from a plant, they had a power failure and when rebooting the MMI's didn't come on. they had to unplug and replug them. i was looking over the help file in Control Logixs 5000 and i found a Power-Up Header. this seems like i need to program something in there for them so that when the power is lost and comes back on then it will all work like it would normally run. thanks Amy