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Posts posted by Rod_Hackney

  1. You need to identify what type of Siemens PLC you are going to use. Then you next task is to determine the communications you are going to use. Wireless, phone lines, sat ect... within the wireless realm there is a license free spread spectrum range and licensed bands. Many questions come up with communications - are the sites in line of site of each other? Does the owner already have a license for freq he uses for scada? After you answer the communications question then you can select hardware that will support that communications with the Siemens PLC you want to use, communication protocol (DNP3, Modbus etc... ) and Scada Software.

  2. I assume this is just distributed I/O via profinet. You should have setup the I/O in your hardware configuration for the Siemens using a GSD file provided by the distributed I/O vendor. This sets up the profinet network. I/O addressing will be assigned by this and you can monitor inputs and outputs just like you use conventional rack based I/O .

  3. You have to use Function blocks in your programming to access the network you are connecting the Siemens PLCS with - You can then transfer data in a client to client type mode.

  4. Ken is right - you will need a plant wide network to facilitate your PLCs connecting to a central server as a start. If you want to produce a plant wide system there are many variables that will have to be planned. You will want to see if each of your processes has a PLC/PLCs controlling them and if ethernet connectivity is available from them.

  5. We traditionally utilize the Allen Bradley standard redundancy setup for ControlLogix hardware. We have had it proposed to go to standard non redundant setup with only redundant power supplies and the utilization of two network cards to provide network redundancy to our HMI. I wanted to get forums experience with the redundant systems. Thanks in advance for your input.

  6. If you want to use the Scadapack unit as a Modbus Master you will need to get a copy of telepace software from control microsystems. It uses standard ladder with master function block that you program to control the modbus communication. It is fairly simple and straight forward. Your device must support Modbus slave functions. The other alternative would be as pauleng states above.

  7. You could upgrade the 5/03 to a SLC 5/05. The SLC5/05 would have a serial port for the existing hmi and would give you an ethernet port for programming or to establish a remote connection.
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  8. Allen Bradley serial port utliizes their DF1 serial protocol. Scadapack serial ports use modbus rtu serial protocol. Telepace is a ladder programming package for Scadapack units made by control microsystems. You do not state which Allen Bradley plc you are using. I assume one of the RSlogix (5,500 or 5000) packages will work to program it. If you have an ifix software package, it runs a driver to get data from the plc. If it is connected to a serial port on the Scadpack, I would assume the ifix MBR driver (serial modbus rtu) is being used. In order for you to connect any device to a serial connection on the Allen Bradley, Scadapack or ifix workstation, it will have to talk the specific protocol native to that device. And either you device or the plc will need to be programmed to transfer data.

  9. uniop is a product provided by Exor Electronics R&D their website is based on the model your using a DF1 driver is available and could be used to communicate with a Micrologix using a serial connections.

  10. Do a limit comparison on the setpoint you are writing down. Write it to the PLC, if it is within limits (using comparison instructions) copy it to a address used in your control. If if is not, copy over a setpoint you assign in the PLC and then perhaps latch an alarm bit to notify the operator.

  11. We have a system we are putting in with a fair amount of field process instruments. We usually use either 4-20 ma wired or foundation fieldbus to connect to our systems. We had a vendor pitching the idea of using ethernet/ip dedicated network for this since some of the instruments being provided support it. We have traditionally only used ethernet/ip for plc to plc or hmi to plc type communications. We have recently interfaced with some of our VFD's using ethernet/ip and it has worked out fine (did this based on a post and references from my friends at mrplc!) Just wanted to see everyones thoughts on this, thanks in advance for your assistance.

  12. If your wanting to use large marquee style signs checkout the signs and ActiveX plugins made by adaptive microsystems. Like BobLfoot said RSVIEW Visual Basic, Wonderware or Cimplicity HMI would be a solution and the ActiveX plugins work well with their displays. I did a project a few years ago with their units and Wonderware.

  13. Pauleng is correct. To eliminate a lot of pain and excessive problems, a scale head is an excellent approach. We had a processing plant that had numerous weighing systems tied in to a SLC500 system as discussed. We had ongoing problems so during a controls upgrade we installed Rice lakes Weighing systems and used their AB interface for ethernet/IP. It has resolved our problems and provided an easier way for the techs to maintain calibration using the Rice Lakes Units.

  14. I would compare a Siemens S7-200 to a allen Bradley micrologix controller, a siemens S7-300 to a compactlogix controller, a siemens S7-400 to a ControlLogix processor. Siemens S7-300 and S7-400 use same programming software support IEC 1131 programming languages. Siemens S7-200 has its own software