Modbus Plus Driver

Open VMS/AXP™ Device Driver for Modicon
ModConnect Series Host Interface Adapters

The IPACT OpenVMS/AXP Device Driver for the ModConnect Series SA-85 Host Interface Adapter (SA85-002), allow an Alpha platform running Open VMS/AXP with an EISA bus to interface with Modbus Plus communications Networks. The driver provides the standard VMS QIO interface for passing Modbus Plus data packets to and from VMS user programs. This driver is a step 2 device driver which requires Open VMS/AXP release 6.1 or greater.

Hardware Support

The device driver supports the SA85-002 Modbus Plus Host Interface (Redundant cable interface only, the SA85-000 is not supported).  The IRQ and base address are hardware selectable, providing users the flexibility to avoid conflict with other EISA/ISA devices and IRQs.  The driver supports up to four SA85-002 devices per ALPHA platform.

 

Software Support

The SA85 device driver for Open VMS/AXP is installed using the standard VMS installation procedure (VMSINSTAL).  The device driver is available on 3.5 inch floppy diskette and optional 4MM DAT.  Installation requires the user to enter the IRQ, EISA bus slot, and base address for each SA85 installed in the EISA bus.  The SA85 serial number and software license number is required for the first SA85 installed in the EISA bus.  All users who can access the internet may request to be added to the IPACT distribution list for any known updates and revisions.  All E-Mail should be addressed to: "mbplus@ipact.com".

 

Documentation

If you like, you can download a copy of the documentation.  This is an Adobe Acrobat (.PDF) File.

 

Supplements for the device driver

• Modbus Plus Interface Library
  This software provides easy read/write access to all Modbus Plus Network Nodes, and allows VMS nodes to be slaves as well as master devices on the Modbus Plus Network. A utility program is provided to diagnose user application programs while they are running. Operator stations that have the ability to access the holding registers of a Modicon 984 Programmable Controller and other Modbus Plus compatible devices, may access the holding registers of a VMS node in a similar fashion. This ability allows the user to integrate data from both the VAX host, programmable controllers, and Modbus Plus compatible devices to the operator without any additional products.

• Modbus Plus Process I/O Scanner
  User tags are defined to a scan generation definition process that generates a VMS global section that can be used by any process within the VMS node. An access library is provided to easily examine the current value of the process variables. Source code is available for custom applications. All outputs should use the Modbus Plus Interface Library. The scanner also supports non-process tags that might be acquired from non Modbus Plus nodes or are calculated within the host computer system. The scanner will also deliver mail to a VMS mailbox upon completion of a scan for historical archival, or host calculated tag computation. Utility processes are provided for fail-over strategies, diagnostics, and maintenance.

Ordering Information

Device Driver for Open VMS/AXP: $1995.00 US dollars per node.
Please contact us directly to order.