TCP Communication Library

 The IPACT Modbus/TCP Communication Library© provides an Application Programming Interface (API) for user written application processes on HP’s OpenVMS systems (Alpha or Itanium).

The IPACT Modbus/TCP Communication Library allows connectivity to Modbus devices capable of modbus TCP/IP over ethernet.  The OpenVMS host is modeled as both a PLC and as a message oriented device.  The following services are provided for OpenVMS application processes:

• Read Input Discretes from a programmable controller.
• Force a single coil in a programmable controller.
• Preset a single holding register in a programmable controller.
• Read or write the extended memory files in a programmable controller.
• Read or write one or more holding registers.
• Read or write one of more coils in a programmable controller.
• Read programmable controller exception status.
• Read/write a register or set of registers as a single operation in a programmable controller.
• Mask write a single register in a programmable controller.
• Read FIFO queue from a programmable controller.
• Virtual Modicon PLC served by OpenVMS host.
• Support for Modbus Plus Slave paths (Remote Master read or write to a VMS host):

1. Write slave path messages to a VMS Mailbox.
2. Suspend and resume the accepting of slave path messages from remote Modbus Plus masters.
3. Read or write OpenVMS holding registers modeled in process memory.
4. 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 register is 40001).  The library is provided as a sharable image and as a linkable object library.

Applications

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

Software Support

The IPACT Modbus/TCP Communication Library is installed using the standard VMS installation procedure (VMSINSTAL).  The Communication Library is available on Compact Disk, 3.5 inch floppy diskette and optional internet distribution.  All users who can access the internet may request the addition of their name to the IPACT distribution list for any known updates and revisions.  All e-mail should be addressed to:  mbplus@ipact.com

Documentation

You may download a copy of the documentation in PDF format.

Ordering Information

Contact us at bz@ipact.com to order.