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Standard Screw Compressor - RWB Series

C-24

M&M

EFRIGERATION

Set Compressor Mode Command

The Set Compressor mode command is used to change the current active mode of the

compressor. Normally, only the Remote and Auto-Remote modes are used by the mas-

ter. Remote mode, when the network is in control, allows the master to provide load and

unload commands for capacity control. Auto-Remote mode allows the master to provide

the control setpoint and the compressor will load and unload to maintain the current active

setpoint.

 NOTE: Some modes are only accepted if the associated options are enabled on the compressor.

Also, if the mode is changed to Local, it may not be changed back to any other mode except

by the operator at the control panel on the machine. If the mode is changed to Automatic or

Manual, compressor Start and Online commands are disabled. The compressor Shutdown

command and setpoint changes will still be allowed. When read, the current value of the

compressor mode will be returned as described in the Compressor mode Table on Page 19.

Change Compressor Capacity Command

The Change Compressor Capacity command allows the master to force the compressor

to load or unload. This command word is only processed when the compressor is in the

Remote mode. When set to 1 or 2 , the compressor will load or unload respectively until

set to 0. When read, the current value of the compressor capacity register will be

returned (1 if the compressor is loading, 2 if the compressor is unloading, and 0 if the

compressor is neither loading or unloading).

Acknowledge/Clear Active Alarm Command

The Acknowledge/Clear Active Alarm command is used by the master computer to

silence the audible alarm horn and to clear alarms from the active alarm display. After

each new alarm or failure, the first control message received with this word set will only

silence the audible alarm horn. Subsequent alarm messages will clear any alarms which

are no longer active. This command is ignored when the compressor is in Local mode.

When read, the current value of the Alarm Status will be returned as described in the See

Alarm Table on Page 18.

Change Current Setpoint Group Command

The Change Current Setpoint Group command is used to change the current active set-

point of the system (Groups 1-4).

 NOTE: This may or may not actually affect the system capacity, depending on the current mode

of the compressor. For example, automatic capacity control is not performed in the

Remote, Manual, or Local modes. When read, the currently selected setpoint group will

be returned (0-3 for Suction Press Groups, 4-7 for Process Temp Groups, and 8 for

Sequenced)

M&M RWB series User Manual

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