AERCO BMS II BOILER - Manual (Page 40)

OPERATION
3-8
RS485 BAUD RATE
The RS485 BAUDRATE option Sets the communication baud rate for the Modbus network
between the BMS II and the Boilers connected to the RS485 terminals [B(+), A(-)]. Available
settings are 2400, 4800, 9600 (default), or 19200.
MIN SLAVE ADDR
The MIN SLAVE ADDR sets the Minimum Slave Address for the Boilers being controlled on the RS485
(Modbus) Network when automatic boiler detection is desired; otherwise, leave set to zero. Allowable
entry range is 000 to 127 (default = 000).
MAX SLAVE ADDR
The MAX SLAVE ADDR Sets the Maximum Slave Address for the Boilers being controlled on the RS485
(Modbus) Network when automatic boiler detection is desired; otherwise, leave set to zero. Allowable
entry range is 000 to 127 (default = 000).
NUMBER NETWK BLRS
This menu option sets the Number of Network Boilers connected to the BMS II RS485 (Modbus)
terminals. Up to 32 Boilers can be connected to the Network (default = 02).
MODBUS CNTL TYPE
This menu option sets the Modbus Control Type to ROUND ROBIN or BROADCAST. Only ROUND
ROBIN can be used at this time. When set to ROUND ROBIN, each networked boiler is addressed
individually in sequence. BROADCAST is currently not used for the BMS II.
NETW BOILER Xx ADDRESS= Yyy (Where Xx = 01 – 32; Yyy = 001 – 127)
Up to 32 Network Boilers can be accommodated on the Modbus Network. Each Boiler must be assigned
a unique address on the network ranging from 001 to127. No addresses should be entered if automatic
boiler detection is desired. Simply set the MIN SLAVE ADDR and MAX SLAVE ADDR to the minimum
and maximum address range of the boilers. To program boiler addresses in the order you desire, enter
them here and set the MIN SLAVE ADDR and MAX SLAVE ADDR to zero.
3.8 FIELD ADJUST MENU.
The FIELD ADJUST MENU contains the most extensive list of options compared to the other 8 Menu
categories. The options in this menu allow you to adjust important parameters to suit the specific needs of
your BMS II installation. Included are options to select the Header Mode and Temperature Limits, Internal
Setpoint, Building Reference Temperature, Reset Ratio and Remote Signal. In addition, the Field Adjust
Menu contains a series of options which can be used to set up a Header Setpoint Offset Schedule for an
entire week. Descriptions of the Field Adjust Menu options:
HEADER SET MODE
The HEADER SET MODE option sets the Header Setpoint selection method for the BMS II. Allowable
selections are: CONSTANT SETPT, OUTDOOR RESET or REMOTE SETPT. (Default = CONSTANT
SETPT).
HDR HIGH LIMIT
The HDR HIGH LIMIT option sets the maximum temperature setting allowed for the Header Setpoint.
This setting also defines the 20 mA temperature equivalent when operating in the Remote Setpoint Mode
using a 4 – 20 mA signal. The allowable setting range is from the HDR LOW LIMIT to 220°F. (Default =
200°F).