Accu EQ Series Installation, Operation And Maintenance Manual - Control Options
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Control Options
Return Water Temperature Display
This option allows the To Process digital display to indicate To Process or Return Water Temperatures. To view the Return
Water Temperature, hold down the Lower Set Point Temperature and Raise Set Point Temperature buttons simultaneously.
Once the buttons are released, the display will return to the To Process temperature.
Remote On/Off Contacts
This option allows the unit to be turned on and off via a remote contact closure. Two terminals are provided in the control
panel to be wired to a remote contact closure device. Switching the contacts from open to closed simulates pressing the
Start button on the control panel. Switching the contacts from closed to open simulates pressing the Stop button. Please
note that the Remote On/Off contacts are nonfunctional until the Power button has been depressed and the control circuit
has been energized. This option also includes a remote/local toggle switch that allows the operator to disable the remote
contacts for safety purposes while the unit is being serviced.
Note: Do not introduce any external voltage to these contacts as this will result in damage to the microprocessor, which will not be covered by the
warranty.
Remote Alarm Contacts
This option includes a set of dry (no voltage induced by chiller), normally open contacts that will close when there is an
alarm condition. Refer to Table 5 for the Microprocessor Control Fault Logic to determine which faults will trigger the
Remote Alarm contacts. The contacts will reopen by clearing the fault or by pressing the Alarm Silence button.
Alarm Horn
This option includes an alarm horn that will be activated by certain faults. Refer to Table 5 for the Microprocessor Control
Fault Logic to determine which faults will trigger the Alarm Horn. The Alarm Horn will be silenced by clearing the fault or by
pressing the Alarm Silence button. If this option is selected in conjunction with the remote control panel, the Alarm Horn
will be mounted on the chiller and not the remote control panel.
Remote Control Panel
This option removes the display and control buttons from the chiller and places them in a small hand-held NEMA 1
enclosure. Included with this option is a 50 foot (15 M) cable to connect the controller and the chiller. All control functions
are available to the operator at the location of the remote panel and no control functions are available at the location of
the chiller.
SPI Communications
This option provides an RS-485 communication port located below the control panel on the front of the chiller. The serial
communications will be multi-drop, half duplex, SPI 3.01 compatible and will allows the unit to communicate with another
piece of equipment that also has SPI protocol capabilities.
The following SPI communications are supported by the microprocessor.
Process Temperature Set Point
High Temperature Deviation
Low Temperature Deviation
Process Status
To Process Temperature
The microprocessor is designed to accept inputs and deliver outputs according to SPI protocol. There must also be a
computer or another piece of equipment that is equipped with the SPI protocol in order for the communications from the
chiller to be of any use. The programming of this computer and/or other equipment is not the responsibility of the
manufacturer.
Note: The manufacturer is not responsible for SPI protocol programming beyond what is included in the microprocessor controller.