Prosoft Technology MVI46-MCM Modbus Communication Module

The Prosoft Technology MVI46-MCM, also cataloged as the MVI46-MCM Modbus Master/Slave Network Interface Module, operates as a dedicated hardware component for serial data communication between SLC 500 rack systems and Modbus-compatible external devices.

Hardware Specifications

Industrial Network Protocol Conversion Latencies

The MVI46-MCM module facilitates deterministic protocol conversion between the SLC 500 backplane and serial field devices. Given the serial nature of Modbus RTU/ASCII protocols, communication latencies are primarily dictated by the selected baud rate and the volume of polling commands configured via ladder logic. The module supports a maximum of 100 commands per port, and users must account for the overhead of register data transfer through the backplane. Proper management of command polling intervals is required to minimize protocol conversion latencies and prevent scan-time spikes within the PLC processor.

Frequently Asked Questions

Q: Can this module be installed in a remote I/O rack?

A: No. The MVI46-MCM is strictly compatible with local or extended rack configurations within the 1746 chassis family and does not support remote I/O rack installations.

Q: Is the configuration port capable of supporting RS-485 communication?

A: No. The dedicated configuration port is exclusively defined as RS-232 and requires the supplied DB-9M cable for physical connection to a programming terminal.

Field Installation Guidelines

• Slot Configuration: The module occupies a single slot within the 1746 chassis. Ensure the backplane is de-energized prior to insertion to prevent potential damage to the module bus connector.
• Wiring and Shielding: When utilizing RS-422 or RS-485 application ports, use shielded twisted-pair cabling. Terminate the cable shield at one end only to mitigate ground loop interference.
• Environmental Considerations: Ensure the installation environment maintains a non-condensing relative humidity between 5% and 95%. Although the module is rated for up to 30 g of operational shock, ensure the chassis is mounted on a vibration-dampened surface to maintain the structural integrity of the backplane connection.
• Termination: When using multi-drop RS-485 configurations, ensure the end-of-line termination resistors are applied according to the specific impedance requirements of the communication cable to prevent signal reflections.