Delta MMC120 User Manual

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Bit 11-12 - State Bits
Bits 11 and 12 show the state of the target generator:

STATE Bit 11 (State Bit B)

Bit 12 (State Bit A)

Stopped

Accelerating

Constant Speed

Decelerating

These bits will also be active when the axis is in open loop (zero output drive, ramping

drive up, constant drive, and ramping drive down).
For example, to detect when an axis’s

TARGET POSITION

has come to a halt after an

'H' command

, monitor for the following status bit combination:

Halt bit

ON (1) (Bit 14)

State bit A

OFF (0) (Bit 12)

State bit B

OFF (0) (Bit 11)

You may also want to monitor the Stopped bit (bit 15).
As another example, to detect when an internal error has caused a Hard Stop or a

transducer error has caused a ramped stop, monitor for the following status bits:

Halt bit

ON (1) (Bit 14)

Open Loop bit ON (1) (Bit 13)

Bit 13 - Open Loop
This bit is set when the axis is in Open Loop. The axis can be in Open Loop because of

'O' command

or because an error caused a Hard Stop.

NOTE: While an axis is in Open Loop mode it may drift due to a valve 'out-of-null'

condition.

Bit 14 - Halt
There are three conditions that will set this bit:

•

Halt (‘H’) command

is issued

•

An internal error causes a Soft Stop

•

An internal error causes a Hard Stop

This bit is cleared when a new command is issued.

NOTE: When an axis is halted (Halt bit ON, State A bit OFF and State B bit OFF)

then the integral drive is automatically set to Null Drive and the Integrator and

Null Drive stop updating. This is done so a Halt command can be given to the

axes when the hydraulic system is turned off or the valves are disconnected so