Programmable Pointer Registers

32 programmable pointer registers are provided for user definition. By using these registers, frequently-accessed drive parameters that may be scattered throughout the register map can be grouped together and accessed with a single holding register read or write command.

Response Delay Function

A programmable network response delay function is available which forces the MDB- 100 to wait a certain minimum time before generating network responses to Modbus commands. This function is useful when equipment such as radio modems (which require a finite time to switch from receive to transmit mode) are used as Modbus network bridges.

Network Watchdog

A network watchdog function is available to detect if communication with the master controller has been interrupted. If an interruption is detected, several different drive actions can be programmed to ensure that the process under control can be safely and automatically driven to a desired state.

Modbus Network Connector

The network interface is a 3-position pluggable terminal block with the following signals provided:

Pin Number

Function

1Modbus network RS485 “A” terminal

2Modbus network RS485 “B” terminal

3Network shield connection point

No network termination is provided on the MDB-100. Be sure to install proper RS485 network termination on the MDB-100 units that exist on the extreme endpoints of the network bus. This can be accomplished by placing a 121Ω (± 5%), 1/2W resistor across the A and B network terminals of those 2 units.

Drive Network Connectors

Uses standard RJ-45 style 8-pin modular connectors. Any standard category-5 ethernet cable (found in most electronics and office-supply stores) 5 meters or less in length can be used to connect the MDB-100 to the drives.

Supported Commands

The MDB-100 presents and receives drive data via Modbus commands 01 (read coil status), 03 (read holding registers), 05 (force single coil), 06 (preset single register) and 16 (preset multiple registers).

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