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  Frequently Asked SY/MAX PLC Questions

  • Which serial cable is needed to program a SY/MAX PLC?
    • The SY/MAX Model 100, 300, 400, 500, 600, and 700 series PLCs all use the same 9-pin RS-422 serial ports. The SC902 is the standard RS-232 to RS-422 converter cable used to connect a PC COM: port to SY/MAX port. This cable may also be used to connect a PC to a NIM, EPE6, MEB, SPE4, IBSM, AIM4, CAM500, SY/LINK board, DLOG, or any other SY/MAX pinout connector.

  • How is an EPE6, MEB, RM14K, SPE4, or UCM4 used without a PLC rack?
    • The NRK2 is used to mount and power a single Niobrara SY/MAX module for stand-alone operation.

  • Must I rack address an EPE6, MEB, or SPE4 PLUS?
    • Only if you are using the mailbox registers for I/O between the module and the PLC. Most installations simply use the card as a protocol translator/router and do not use the mailbox registers at all. The module may often be placed in slots 17 and 18 on an HRK300 rack.

  • When is the external power supply needed on the SC902 cable?
    • The external power supply is needed on ports that use active RTS/CTS RS-422 handshaking such as the following:
      • All Square D NIMs
      • Square D SFI-510 SY/LINK RS-422 port
      • SPE4-1D and SPE4-2D Ports 1, 2, 3, or 4
      • AIM4-1D, AIM4-2D, and AIM4-2M Ports 1, 2, 3, or 4
      • UCM4-D and UCM4-M Ports 1, 2, 3, or 4
      • RM14K
      • All EPE6 RS-485 ports
      • All MEB ports
    • Many SY/MAX ports provide 5VDC so the external power supply is not needed on the units that follow:
      • All Square D PLCs (Model 100 or greater)
      • Every SPE4 Port 0
      • Every AIM4 Port 0
      • SERI
      • CAM500
      • IBSM

  • Which serial cable is used to replace a Square D ICM200?
    • The SC902 may be used to replace the ICM200 in most situations but there are a few differences:
      • The ICM200 is optically isolated while the SC902 is not isolated. For an optically isolated system use the DDC2I-5 and a DC1 cable.
      • The ICM200 provides 4-channel RS-232<>RS-422 conversion which means RTS and CTS are active. The SC902 is a 2-channel converter and RTS and CTS are simply jumpered at each end. So if the ICM200 is used in a push-to-talk radio system then the SC902 will not work properly.

  • Which serial cable is used to replace an old Niobrara SC406?
    • The SC902 is the replacement for the old SC406 cable. The SC902 has a 9-pin RS-232 end to connect to todays PC serial ports.

  • How do I update the firmware of my Niobrara SY/MAX module?
    • The following NR&D modules have FLASH firmware that may be upgraded in the field with the module's sofware and a serial cable. See the user manual for the particular device for extensive instructions on firmware upgrading.
      • AIM4-3S or AIM4-3D
      • EPE5-TCP, EPE5-T, EPE5-ST, or EPE6
      • IBSM or IBSM PLUS
      • MEB, MEB-TCP, MEB-T, or MEB-RT
      • PEN-T or PENT-SA
      • SERI
      • SPE4-3S or SPE4-3D
    • The following NR&D modules use EPROM firmware that may be upgraded in the field but require chips to be shipped from Niobrara. An RMA is required for firmware upgrades on the following modules. Upgrades involve using a screw driver to remove the side of the module and the removal and replacement of one or more socketed ICs. An upgrade fee is charged for units out of warranty. Instructions are included with the firmware chips.
      • AIM4s that are not -3 versions
      • CAM500
      • Non-TCP versions of the EPE5
      • IBSS
      • All AUI versions of the PEN
      • PMN
      • RM14K
      • SPE4s that are not -3 versions
      • SPXM
      • UCM

  • What is the difference between the IBSM and IBSM PLUS?
    • The old IBSM only used an 8 bit buffer for the backplane interface with the PLC. This sometimes results in the PLC reading 1/2 of a register while the IBSM is updating the other half which may result in bogus data being transfered. This problem is most pronounced when analog values are near the 255 or 256 value and is usually not a problem with discrete bit I/O. The IBSM PLUS fixes this problem by using a full 16 bit backplane interface that ensures data word integrity across the backplane.

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