Modbus Plus Library

The IPACT Modbus Plus Communication Library© provides an Application Programming Interface (API) for user written application processes on Hewlett Packard's Open VMS/AXP systems equipped with EISA BUS and SA85-002 or Open VMS/VAX equipped with Q-BUS and SQ85.  The corresponding software device drivers must also be installed.

The IPACT Modbus Plus Communication Library© allows connectivity to the Modbus Plus Network as a normal Modbus Plus node.  The VMS host is modeled as both a PLC and as a message oriented device.  The following services are provided for VMS application processes:
 

• Read Input Registers
• Force a single coil in a programmable controller  
• Return Modbus Plus Adapter device status registers
• Return Modbus Plus Adapter network counters
• Return any Modbus Plus Node's slave id
• Preset a single output register
• Read and write the extended memory of a programmable controller
• Read and write Modbus Plus Network global data
• Read and write one or more registers of a programmable controller
• Support for Modbus Plus Slave paths (Remote Master read or write to a VMS host)
• Write slave path messages to a VMS Mailbox
• Suspend and resume the accepting of slave path messages from remote Modbus Plus masters Read or write VMS holding registers modeled as process memory
• Read Modbus Plus Network unsolicited messages from the OpenVMS mailbox

The API calls are provided in both synchronous and asynchronous versions.  All calls to the API use the same numbering convention as the Modicon PLCs (e.g. the first holding registered is 40001).  A general purpose scanner is provided to scan Holding Registers from Modbus Plus slave nodes.  The library is provided as a sharable image and as a linkable object library.

Applications

Process Simulation & Staging	Process Monitoring
Process Model Integration	Process Data Collection
Recipe Downloads	Human-Machine Interfaces

Software Support

The IPACT Modbus Plus Communication Library is installed using the standard VMS installation procedure (VMSINSTAL.)  The Communication Library is available on 3.5 inch floppy diskette and optional 4MM DAT.  All E-Mail should be addressed to: "lakia@ipact.com".

Documentation

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

Ordering Information

IPACT Modbus Plus Communication Library© for Open VMS:  
$7,400.00 dollars per node. Please contact us directly to order.

Integrated Process Automation & Control Technologies