WALKER TECHNOLOGIES CORP.

Products / Programming

Programming

Programming Made Easy!

• Each SAC contains it´s own OS
• An executable database which defines the connected points
• GCL programs which reside in the database & define the required control procedures

Each Stand Alone Controller (SAC) contains its own Operating System (OS) stored in nonvolatile memory. This OS provides the intelligence required for all levels of energy management and control.

To create specific control functionality, an executable database which defines the connected points and the required control procedures can be created. This database activates the OS functionality when it is required. Access to any connected SAC is available through the Connect-2004 front-end or through a portable operator terminal connected to a WS1600 Node or WS1616 SAC.

The SAC database format is constant throughout the Walker product line. Control programs in any SAC can also be loaded and executed by any other past, present or future SAC type. Therefore, system expansions are fast and simple: databases are saved to disk, then loaded into new controllers, and operation is restored without any further programming.

As the Walker product line evolves, OS versions can be upgraded without the need to change out EPROM chips in MiniSACs and MicroSACs. This feature provides substantial savings in large systems.

SAC Database Functionality

The SAC database includes software points for all energy management functions, as well as the following features:

• Fixed function (canned) or custom programs	• Dial in/automatic dial out capabilities
• User-defined labels for all points in all SACs	• External control system interface capabilities
• Single point revisions	• Interval/COV/COS trending for all database point

DATABASE

Intelligent panels make customizing easy
• Created by system installer or operator
• Controls the SAC's functionality
• All Walker panels use the same database
• Database is backward compatible to 30 year-old installations
• Build via WS1600 or WS1616 or use our front end software CONNECT-IMS

GCL - GENERAL CONTROL LANGUAGE

Plain and simple

• Available in all SAC panels
• All database points accessed via GCL
• Closely resembles conversational English
• Build via WS1600 or WS1616 or CONNECT-IMS
• Database is backwards compatible all the way to the original products

DATABASE ACCESS POINTS

Finding the Source

VARIABLES:	Four types of variables are provided
ALARM:	Monitors any point for high and low limit conditions
CONTROLLER:	PID controllers feature true elapsed time calculations
TOTALIZER:	Totals the time and number of starts for any point
INPUT/OUTPUT:	Defines the external connection to the system and sensors
DISPLAY:	Can contain up to eighty system points
ASCII:	Defines external database mapping
SCHEDULE:	Weekly and annual schedules
COMMAND:	Used to trigger alarm and activity reports or remote dial-out

GCL LANGUAGE CONSTRUCTS

Full programmability creates infinite flexibility

+, -, *, /	Add, Subtract, Multiply, Divide
SQRT( ), ABS( )	Square Root, Absolute Value
IF, THEN, ELSE	Conditional decision branches
<, >, =, ><	Less, Greater, Equal, Not Equal
BETWEEN	Between
AND, OR, XOR	Boolean operators
ON-FOR, OFF-FOR, ON-FOR<, OFF-FOR<	Start/Stop time delays, minimum and maximum delays
DO-EVERY	Periodic control action
GOTO, CALL	Program redirection
START, STOP	Start and stop control
DATA	Data extraction from any point
C-ON, C-OFF	Supervisory program control
HOUR, DAY, MONTH, TIME, DATE, WEEKDAY, HOLIDAY	Time scheduling functions
MESSAGE	Message output to terminal modem port or external system.

GCL CODE EXAMPLE

No cryptic codes

[ ADMINISTRATION FAN CONTROL ]

IF DAY SCHEDULE ON THEN
            DAY_OPERATION
ELSE NIGHT_OPERATION

            :DAY_OPERATION
            START SUPPLY_FAN, RETURN_FAN
            HEATING_COIL_VALVE = (AIR_SETPOINT - AIR_TEMP) * HEATING_COIL_GAIN
            HEATING_COIL_VALVE = MIN ( HEATING_COIL_VALVE,100 )
            RET

            :NIGHT_OPERATION
            [ ALSO MUST CHECK NIGHT SETPOINT ]
            IF AVERAGE_TEMPERATURE < NIGHT_SETPOINT THEN
            DAY_OPERATION
            ELSE
            STOP SUPPLY_FAN, RETURN_FAN
            HEATING_COIL_VALVE = 0
            RET