Control Techniques Digitax ST

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Parameter

structure

Keypad and

display

Parameter x.00

Parameter

description format

Advanced parameter

descriptions

Serial comms

protocol

Electronic

nameplate

Performance

98 Digitax ST Advanced User Guide

www.controltechniques.com Issue Number: 1

The drive comms system 128 bytes buffer used with ANSI or Modbus rtu protocols via the 485 connector can be controlled by a Solutions Module

under certain circumstances. This parameter shows which node has control of the buffer (0 (drv) = drive, 1 (Slot1) = Solutions Module in slot 1, etc. If

a Solutions Module has control of the buffer the drive will use an alternative buffer for 485 comms and the following restrictions will apply:

1. Comms messages via the 485 port are limited to a maximum of 32 bytes

2. The 6 pin keypad port will operate correctly with an LED keypad, but it will no longer operate with an LCD keypad

3. Modbus messages using the CMP protocol can only route messages to nodes within the drive. It will not be possible for these to be routed further,

i.e. via CT Net on an SM Applications module.

When a drive with an internal rectifier is used this parameter should be left at zero. For a drive with an active external rectifier (used to control DC bus

charging) this parameter should be the destination of the output of a variable selector set up for external rectifier monitoring. This allows the

monitoring block to prevent the drive from leaving the main loss ride through mode until the rectifier is fully active and phased forwards. If this feature

is not used the mains loss ride through mode ends as soon as the DC Bus voltage is above the mains loss detection level. The rectifier may still be

phasing forwards and the application of load at this point may cause the DC Bus voltage to fall back below the mains loss detection level again.

6.50 Drive comms state

Coding