York 00497VIP manual Stop Command, and Current / Load Limit can be

CHILLER/CONDENSING CONTROL PANEL(S)

All communication with the chiller/condensing units will occur over a single RS-485 port. Reference Figure 2 and the Installation instructions.

When the OptiView RCC is first turned on it will initialize by requesting current data and history buffer information from the units connected. After the history buffers are filled, only current data will be continuously requested. Every eight hours the OptiView RCC will re- initialize. If the control panel updates the history buffer (a safety shutdown has occurred), the control panel will send the chiller shutdown data to the OptiView RCC upon receipt of the next valid OptiView RCC transmission. The OptiView RCC will recognize that a safety shutdown has occurred by the Update History Buffer bit being set. If this bit is ever 1, the data dump is assumed to be a shutdown data dump and the OptiView RCC will update its history buffers with the new data and start a printout of the transmitted data through its RS232 port. If the OptiView RCC had been requesting another type of data dump (i.e. a daily schedule dump), the OptiView RCC will repeat its request on the next transmission.

While at the Home Screen, the OptiView RCC will communicate with each unit in order. Once a unit has been selected by entering the Unit Screen or any screen below it, that unit will be polled between every unit in order. This will allow the selected unit to update its information quickly while still maintaining information for the Home Screen.

A command string is used to indicate what data the OptiView RCC is requesting and to modify control data in the chiller control panel. If the chiller/condensing unit is in remote control mode then its Local Set Point, Local Range, Daily Schedule, Holiday, Start

FORM 50.40-OM2

/ Stop Command, and Current / Load Limit can be
programmed from the OptiView RCC. The OptiView
RCC will send a command string once any of these are	1
modified at the OptiView RCC. If the OptiView RCC

sends a Stop command, the chiller/condensing unit will turn off. If the OptiView RCC sends a start command, the chiller/condensing unit will be allowed to run if all the other run requirements of the unit are made.

A chiller/condensing unit that is in remote control mode will use local control (set points and start / stop information), if a valid transmission has not been received for 5 minutes from the OptiView RCC. The remote commands will be used again once a valid new transmission has been processed. The OptiView RCC will display an error message indicating the communications problem when such a condition occurs.

A general status message for each unit is displayed on the Home Screen. The messages displayed will include communications status. Not Initialized will be displayed upon power-up for all units until the OptiView RCC begins to poll and receive data from that unit. Initializing… will be displayed while the OptiView RCC is polling a unit for all current, schedule, and history data the first time after power-up. Loss of Comms will be displayed after 5 minutes have elapsed with no response from a previously initialized unit. If any of these messages is displayed, the unit’s button will be disabled not allowing it to be selected.

The Control Center Microboard (J12) communicates with this board via a 0/+5VDC serial data communica- tions link. If this communications link does not operate properly, correct Microboard J12 serial port operation can be verified using the Serial Inputs and Outputs diagnostic procedure in the “Service” section of this book.

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