Page 12 IM 781-2
General Description
The Chiller System Manager (CSM) provides start/stop capability, scheduling functions, sequencing, load limiting control,
system chilled water temperature control, secondary loop water flow control, cooling tower control, alarm processing, and
alarm generation for a chiller plant.
The CSM consists of a hardware platform and software, which is accessible with a Web User Interface (WebUI). The
hardware consists of a main processor, onboard I/O module and optional remote I/O module(s). The main processor and
onboard I/O module are assembled together within the CSM cabinet. The optional remote I/O consists of distributed
input/output modules, which are mounted independently of the CSM cabinet. The remote I/O modules communicate with
the main processor through a L
ONWORKS communications network. McQuay offers stand alone remote I/O modules for
mounting in a field enclosure or remote I/O panels with modules mounted inside. This document describes the wiring to
the remote I/O modules for application of the CSM. For information on mounting and power wiring for a remote I/O
panel, refer to IM 783-Remote I/O Panel Installation Manual. The CSM onboard I/O module may be sufficient for your
chiller system control.
The CSM software within the main processor will execute all control functions to manage the chillers and all I/O in the
CSM and remote I/O modules. The CSM software communicates with the chiller unit controllers using L
ONWORKS
communications. Multiple control strategies operate in the CSM software and are configurable using the WebUI.
The WebUI consists of web pages served from the CSM. These web pages are accessible from any computer running
Microsoft Internet Explorer and connected to the Ethernet port on the CSM. The WebUI is used to edit control system
input parameters required for multiple-chiller control algorithms and to set certain parameters in the chiller controllers as
necessary for multiple-chiller control. The multiple-chiller control strategies will provide automatic control of chillers
connected to the CSM.
The CSM is capable of communicating with a connected BAS using BACnet/IP, BACnet Ethernet, or Modbus (Modbus
RTU or ASCII over RS-485 or RS-232 ports) in accordance with the communications protocol used by that system. The
Modbus driver is optional and licensed only when ordered.
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