Specifications

Section 2—Modbus Plus Overview Bulletin No. VVDED397044US R12/00

Hand/Off/Auto (HOA) December 2000

before the MODBUS PLUS communication board has initialized and

assumed control.

This can result in unintended equipment operation.

When the control switch is in the hand or off position,

the drive controller

must be placed into the forced local mode .

While it is possible to stop

the drive controller in the remote mode by activating one of the local stop

commands (such as the keypad display stop button), commands sent

over the network can restart the drive controller if it is not in forced local

mode. See “Forced Local” on page 53.

Refer to Figures 28 and 29 for assistance in designing Hand/Off/Auto

control. For the run reverse and forced local functions, select any unused

logic inputs on the main control board. Assign a logic input to the run

reverse function only if appropriate for the application.

Figure 28: Example 2-Wire Control

NOTE: When the HOA switch is in the auto position, removing the local

run forward or run reverse commands does not stop the drive controller.

Figure 29: Example 3-Wire Control

Hand Off Auto

LI1 Run Forward

+24

LIx Run Reverse

LIy Forced Local

User

Control

Scheme

Hand Off Auto

+24

Stop

Fwd Rev

LI1 Stop

LI2 Run Forward

LIx Run Reverse

LIy Forced Local