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About d0ubleth1nk

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  • Country Canada
  1. Does anyone know how the maximum distance a 120 VAC digital input loop is allowed to be? I'm having a float switch in a diesel tank wired, but it's 70 meters from the PLC, so 140 meters for the loop. Thanks.
  2. I'm looking for a signal isolator/repeater, that can accept 2 current loop inputs, and based upon a seperate digital input, only repeat 1 of the input signals. Is there such a device, and who makes it? Thanks.
  3. Ethernet router for leased-line

    Thanks Ken. We spec'd MuLogic for the City of Chicago Water System and had nothing but trouble, plus their from Holland so tech support was crazy to setup. This project is using a voice grade leased line. Bascially I want a router with an embeded voice grade modem for this type of application, but no one manufacturer makes such a device. I ended up emailing N-Tron, Hirschmann, Cisco, Phoenix Contact and Black Box. Only Black Box has a solution using a modem and a router with a serial connection for both ends. It can't be worse than MuLogic.
  4. I'm trying to get an Ethernet connection to a remote valve chamber that has an existing lease-line. I need a router (or any device) that connects on both ends of the lease line, that has has Ethernet connections for the PLC at the valve chamber and the network switch at the HMI. Any ideas?
  5. 9300 RADES and leased lines?

    I've been searching high and low to see if this AB ethernet modem can be used with a leased-line? I'm not a modem expert but since this is a "dial-up" modem, does that mean it can't be used with a leased line since there's no dial tone? Thanks.
  6. L35E CPU Ethernet Fail

    I definetly could not ping the CPU during the failure so I suppose it's not a CIP problem. Also the stats page says that I've never maxed out CIP connections as there's a total of 8 from the Panelview and DASCIP. This isn't a man'd plant so the failures happen during normal operations and no editing. The network is comprised of the CPU, HMI, OIT and a SLC505 for a vendor grinder system at headworks. Come to think of it, comms to the SLC is not trustworthy as it goes in and out. The contractor is trying to get the electrical sub to pull a new CAT 6 cable. There's been much bigger issues to deal with, but I should finally get around to looking at the SLC comm fail and see if that is somehow tripping the Compactlogix. We recently upgraded the firmware as Rockwell always friggen suggests firmware, but in my experience it rarely does anything. Thanks for the suggestions!
  7. L35E CPU Ethernet Fail

    The HMI is Wonderware and the OIT is a Panelview. Both give general Communication failure alarms on timeout. No error codes that describe what's happening at the RPU level. I always spec a Phoenix Contact switch, that has never given me trouble in the past. When the CPU ethernet hangs, the network is still alive and well where I can connect my laptop and ping everything except the CPU. I cannot connect to the CPU through the ethernet port, but I can still go online serially. RSLinx has the CIP diagnostic feature that mentions the CPU is not accepting CIP connections. To reset the ethernet portion there's a reset button under the ethernet properties and "Module Info" tab. In using the web browser after restting the ethernet card, the stats page tells me my "CIP Msg Connection Limit" is 32 and "Max Msg Connections Observed" is 8. I'm not a network expert but all the stats appear good and nothing jumps out as being problematic.
  8. L35E CPU Ethernet Fail

    I'm pretty sure the configuration of the ethernet port is okay as comms is fine for 2 months. Bootp has been disabled the whole time. The only thing sticking in my mind is the RPI under the "Connection" tab is static at 0 ms. Even offline I can't modify it. There's also an RPI under the backplane that I have set at 100 ms. From what I've read the RPI has to be something greater than 2 ms, but if both of the RPI's are the same then I'm fine.
  9. L35E CPU Ethernet Fail

    I have a CompactLogix L35E where the ethernet portion of the CPU dies every 2 months. The CPU still runs and the plant is fine, but the HMI and OIT are blind until I connect serially to the RPU and reset just the ethernet. The "NS" light blinks continually during the error and which means: "The port has an IP address, but no CIP connections are established." Why is the ethernet portion of the card hanging? Everything is hardwired and it's just the single RPU so no ethernet messaging or anything. Thanks.
  10. GE 90-30 Questions

    Thanks for the quick response!
  11. CompactLogix CPU Battery

    I’m investigating some unusual events with a CompactLogix controlling a small sewage plant. The RPU was installed in April (2010). In August, there was an extended power outage, where the genset failed and the UPS for the panel eventually died. When power came back, there was no program in the RPU as the CPU battery was dead. Then there were issues with a communication loss from the CPU to an IO module, that faulted the processor almost daily. The CPU and PS were replaced, and a new battery came with the new CPU. Everything ran fine until last week. Again the CPU faulted from loss of comms to some IO card, and the battery was dead again. After a series of tests I figured out there was a problem with a dosing pump connected to an AO card where the pump was not properly grounded and there was 48VAC potential at the pump AI. The AO card is rated for 30 VDC max. I replaced the AO card, added some signal isolators and everything seems to working fine. The client has major reservations about the dead PLC battery, and all I can tell them is that the AO card problem must have killed the batteries, but not the CPU’s. Any idea’s how the CPU batteries have been dieing?
  12. GE 90-30 Questions

    Hello, I'm designing an I&C upgrade that effects an exisiting 90-30 network. My questions are: 1. Can you use PME 6.0 to communicate to a CPU 364? If not, what software should be used? 2. To communicate between two CPU 364's are EGD's used? (like between Rx3i's) If not, how do two CPU 364's share data? 3. If a 90-30 chassis has an "RTU Master" module, polling Modbus slave devices over RS-485 network, what changes are required to add another device, ie. another RS-485 drop? Is it just some programming changes to add more logic to poll a new Modbus device address and Modbus tag addresses, or is it a change to something like an EGD (but a serial version?) ? Basically is it logic changes or configuration changes? Thanks.