Lochinvar Armor 101 Series, Инструкция по эксплуатации

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21
ModBus and BACnet Instructions
Temperature
Th e Armor passes temperature data in degrees Celsius. Also, to
accommodate decimal places the decimal value must be divided
by 10.
Here are the conversions to and from Celsius:
T
c
= (5/9) * (T
f
-32) T
f
= (9/5) * T
c
+32
Rate and Temperature Conversions:
Rate
When issuing a rate command the rate can be communicated
as percent modulation or a desired setpoint, depending on
the setting of the BMS Type in the BMS Setup Menu.
Th e proper data format for the modulation percentage is the
direct conversion to hexadecimal. Th is conversion can be
accomplished through online number based converters or
some scientifi c calculators.
For Example:
To send a desired setpoint, the hexadecimal value must be
determined through linear interpolation of programmable
parameters on the BMS Setup Menu:
- BMS temperature set-point at low analog input
- BMS temperature set-point at high analog input
Th ese variables set the temperature values corresponding to
the minimum and maximum voltage settings of the 0-10 volt
signal. Th
e defaults are as follows:
Rate % HEX
0 00
20 14
45 2D
60 3C
80 50
95 5F
100 64
PARAMETER
DEFAULT
VALUES
DEFAULT
Deg C Deg F Voltages
BMS temperature setpoint at
low analog input
21 69.8 2
BMS temperature setpoint at
high analog input
82 179.6 10
For Example:
Send a setpoint of 110°F.
Th e formula to use for the interpolation is:
Rate Command =
(Desired Setpoint – BMS Temp at Low Analog Input) (High
Voltage-Low Voltage) + Low Voltage
(BMS Temp at High Analog Input – BMS Temp at Low
Analog Input)
From the default values:
Desired Setpoint = 110
BMS Temp at Low Analog Input =68
BMS Temp at High Analog=158
High Voltage =10
Low Voltage = 2
[(110-69.8)(10-2)/(179.6-69.8)] + 2 = 4.92 Volts
(4.92/10) x 100 = 49.2
49 = 31 Hexadecimal
A value of [00][31] in hexadecimal would be written to Holding
register 40003 to issue a command for a 110°F setpoint.
7
Unit Operation
(continued)