Dc Device Control Function Block - Honeywell HC900 Reference Manual

DC Device Control Function Block

Description
The DC label stands for Device Control.
This block is part of the Auxiliary category.
Function
The Device Control function block is normally used to control pumps. Based on certain events listed in
T able 38 the device will be placed into one of six states: READY, PRESTART, STARTING, RUNNING,
H
STOPPING, DISABLED, or FAILED. The READY (off state) is the initial state of the function block.
Each configuration is limited to a maximum of 16 Device Control function blocks.
Forcing of outputs is NOT permitted within this block.
Inputs
REQ = (run request) when ON [Logic 1], puts the device in the Starting / Running state. When OFF, puts
the device in Stopping / Ready state.
FDBK = feedback from the controlled device; ON = device has started, OFF = device has not started.
ERR = (in) – ON when the controlled device reports a failure, causes the device control to transition to the
FAILED state.
OFF = No device failure.
^RST = an OFF to ON transition will manually reset the control when it is in the FAILED state and return
to the READY state.
DIS = (disable) When OFF, the device control operates normally. When ON, immediately transitions to
the DISABLED state, it prevents the device from starting if in the ready state or immediately shuts-down
the device if it is currently starting up or running state.
Revision 11
2/07
HC900 Hybrid Control Designer Function Block Reference Guide
Function Blocks
DC Device Control Function Block
121