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To set up optimal start control
1. Command the Optimal Start Flag to “OS Enabled”
2. If you want the CSM to automatically adapt to your Optimal Start characteristics set the Auto Update Flag CWRT Flag
and/or Auto Update OAT Flag to “Yes.”
3. Set the Optimal Start Begin Recirculate Period to the desired time period before the scheduled start time which optimal
start-up will run the cooling load pump(s) for a temperature sample.
A typical setting would be about one hour before the normal scheduled start time
4. Set the Optimal Start Recirculation Period to the amount time you want the cooling load pump(s) to run before the
CSM takes a temperature reading at the return chilled water sensor.
The CSM requires an accurate return water temperature to estimate the load and thus the optimal start-up time.
Note: The CSM’s optimal start feature works only with systems that have at least one cooling load pump. To use the
optimal start feature, chilled water supply and return temperature sensors must be connected to the CSM. In addition,
an outdoor air temperature sensor must be connected to the CSM.
BAS Communication
The CSM may be configured for integration into either a BACnet or Modbus BAS.
BACnet Settings
The CSM may be integrated into either a BACnet/IP or BACnet over Ethernet BAS. In either case, connection to the
BACnet network is done through the CSM’s Ethernet port. See ED 15075 for more information on the BACnet protocol
data points. Configuration properties for both are described below. To configure the CSM for BACnet communication, go
to the BAS Config screen to change the values described in Table 20. To configure the CSM for Modbus communication,
go to the BAS Config screen to change the values described in Table 21.
Table 20. BAS Config - BACnet (Main > Configuration > BAS Config)
Name Description
BACnet Device
Instance Number
BACnet device instance number of the CSM. This must be unique to the BACnet network Range = 0– 4194304. Default = -1
BACnet IP
Configuration –
Enable (BAS
only)
Setting this value to Yes enables the CSM’s Ethernet port for BACnet/IP communications. If there is no BACnet/IP BAS, this
variable should be set to No. Range = No, Yes. Default = No
BACnet IP
Configuration –
Network Number
The Network Number must be unique for each BACnet network segment. All BACnet/IP devices on all BACnet/IP segments
must have the same BACnet/IP Network Number. Range = 0 to 65534. Default = 1001
BACnet/IP
Subnet Mask
A subnet mask is a 32-bit number, written in dotted decimal form. Only BACnet/IP devices that are on the same subnet can
communicate with each other without a router. Default = 255.255.0.0
BACnet/IP UDP
Port
The UDP (User Datagram Protocol) port number is used by the client or server device for sending or receiving messages. Taken
together with a network address (IP address), a port number identifies both a device and also a “channel” within that device
where network communication will take place. Note that the UDP Port string entered from the user interface requires the “0x”
prefix on the hexadecimal value. Default = 0xBAC0 (47808 in decimal)
BACnet/IP
Device Type
If BACnet/IP broadcast messaging through IP routers is required, there are two possible configurations. Another BACnet/IP
device on the same subnet as the CSM can be the BBMD (set this value = none). The CSM can function as the BBMD on it’s
subnet (set this value = BBMD and input another BBMD’s address into the Remote BBMD Address field). Do not set the CSM
up as a BBMD if another BBMD already exists on the same subnet or communication problems will result. Range = none,
BBMD. Default = none
Remote BBMD
Address
If the BACnet/IP Device Type variable = BBMD, you need to enter the known address of another BBMD on your BACnet/IP
network here. Entry format requires all hexadecimal with colons; xx:xx:xx:yy:yy where xx:xx:xx:xx is the IP address and yy:yy
is the UDP port of the remote BBMD device. Use Windows
®
Calculator to convert IP octets from decimal to hex. The CSM
must be shut down for 3 minutes (or until all LED’s go off) and restarted for this change to take effect. The CSM will
automatically fill in its Broadcast Distribution Table from the remote BBMD after startup. Default = null
BACnet Ethernet
Configuration –
Setting this value to Yes enables the CSM’s Ethernet port for BACnet over Ethernet communications. If there is no BACnet
over Ethernet BAS, this variable should be set to No. Range = No, Yes. Default = No
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