lonegator

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About lonegator

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  1. I have a project that I'm doing the automation for and wanted to throw my scenario out there to see if anyone could offer some advice/suggestions: The project involves multiple smart MCCs, meaning each motor's MCC bucket has a motor management controller.  These controllers are all connected to my PLC via Modbus...so I have no hard-wired outputs for motor control.   There are multiple e-stop stations throughout the plant, that are wired back to my PLC panel(s), however, the customer did not account for a hard-wired e-stop circuit and expects me to use the PLC for an emergency stop.  Even though in a recent call to my local MSHA office, I was told that they have no regulations for a full plant e-stop just individual machine e-stops, it's my company's policy (and my personal policy) that we NEVER program in a PLC-controlled e-stop.  There is way too much risk and liability involved in this. First off, I know the PLC-controlled e-stop situation has been discussed multiple times before.  Can anyone direct me to any legal literature or guidelines that explain the dangers behind this?  My customer isn't buying the "it's my company's policy" thing, and I'm being pressured by my GM (who knows nothing about the automation side of our business) on why we have this policy in the first place.  I would like to be able to give them all some official document backing my stance so they'll get off my back. Secondly, does anyone have any suggestions on any possible way for me to do an approved e-stop circuit in this situation?  The customer has pulled back the wires from every remote e-stop station to my PLC.  I'm ignorant when it comes to safety controllers and safety relays.  Can I wire the e-stops through a safety controller or relay and communicate that back to my PLC in some way?  Is that permissible?  Short of killing power to the PLC during an e-stop, I don't know what I can do on my end.  I've told my customer that the e-stop circuit needs to be wired through each motor bucket and showed them on the MCC schematics where the manufacturer accounted for a customer-supplied e-stop, but they didn't like to hear that and would like another solution. Any help would be greatly appreciated! 
  2. Configuring Remote PLC Access With Two NIC Cards

    That makes sense. Could I temporarily bridge the connections and configure back to normal when the programmer is done? If so, what is the procedure for creating the bridge and what needs to be open on the router for the programmer to have access?
  3. I wanted to see if someone can fill me in on what I need to do to get this working (or if it's even possible)...My HMI PC has two NIC cards. The first is directly connected to a switch in the control panel which gives me access to the PLC. It's IP address is 192.168.1.21 and has no gateway. The 2nd cards is connected to my company's Internet. It has an IP address of 192.168.0.106 and a gateway of 192.168.0.1. Is it possible to bridge these connections and open up my Internet to give a remote programmer access to the PLC program in case we need changes made? I'm new to this so if someone could provide steps on what I need to do, I'd really appreciate it. Thanks!
  4. PID Block Assistance In RSLogix 500

    TPH = TONS PER HOUR I will get the information you requested this evening. Thank you for the reply.
  5. I have a customer who needs conveyor speed to adjust based on TPH. In other words, they are going to key in a number (let's say 100 TPH) on the HMI screen based on what they want to produce. The conveyor speed will adjust accordingly to produce this amount, based on what the weigh belt is reading. I'm assuming a PID block will take care of this for me, but I've never used one before. Can someone point me in the right direction? I will have the HMI entered TPH, the actual reading from the weigh belt, and an input to adjust the conveyor speed to work with. If you need more information, let me know. Thanks for any assistance provided!!
  6. TON Help

    Can someone look over the attached line of logic and let me know what I have wrong? The TON's .DN bit never sets and the timer just continues over and over again. Thanks!
  7. PID Function - Help Needed

    Hello everyone. I am fairly fluent with the basics of PLC programming but am totally uneducated on some of the lesser-used functions (at least lesser-used by me). One such function is the PID function and I wanted to see if someone could explain how to properly use it, based on my scenario. I am onsite at a river/rail terminal for coal. They've installed a new conveyor system to transfer the coal from river barge to ground and then have 4 new conveyor lines used to create different blends of coal. I'm working on these blending lines. I have everything working but want the best method for producing their desired tons per hour. For a line, they enter in an initial conveyor speed and desired TPH and start the line. A belt scale attached to the line measures the actual TPH and sends this to the PLC thru a 4-20 mA signal. I need to compare the actual TPH with the desired TPH and then adjust the conveyor speed +/- accordingly. I have tried reading up on the PID function but just am not grasping it. Can someone let me know how they'd suggest I handle this scenario? Any ideas would be greatly appreciated!! If you need more information to provide an adequate solution, just let me know. Thanks!!
  8. Cables Needed When There's NO 8 Pin Serial Port

    I meant 9 pin... My dilemma is that our general manager doesn't see the need to fork out an additional $1,000 just to get a laptop with a serial port (when I've read on here that most of you never have any problems connection to MicroLogix processors which is mostly what we deal with). From what I can find, I'm going to pay at least $1,500 for a decent, new laptop with a serial port and on NewEgg right now, I can get a decent laptop w/o a serial port for $500. As hard as our service guys are on laptops here, that's much more cost effective and if the USB to serial adapters work sufficiently, we're going to have to go with the cheaper laptops. We have 4 older laptops that still work and have serial ports. If any of our service guys need to connect to something else and don't feel the USB to serial adapter will work, they can take one of the older laptops along as a backup.
  9. Hello All. I'm the IT Manager here and need to purchase some new laptops for our Service/Engineering department. I'm trying to convince our guys that they can do what they need to do without the serial port but am receiving a lot of flack. Can someone list out all the cables needed when connecting thru a USB port? We deal mostly with MicroLogix and ControlLogix. Also, though I'm in the A-B forum, I haven't investigated this too heavily yet but assume that USB conversion cables are available for the other brand name PLCs and drives. Is that correct? I purchased a USB 1747-CP3 and a 1761-CBL-PM02 and tried to connect to a ML 1200 but didn't have any success. Could someone also list out the steps to successfully connect using these cables? Thanks for your assistance. Doug