Modbus Communications (continued)
Network/Modbus
®
Communications 91
XRAM Variables
These variables can be read using Modbus
®
command 03 Read Holding Registers. They can
be written to using Modbus
®
command 06 Write Single Register. Many of these variables are
the same “menu items” that are configured from the controller keypad. The calibration and control
items are not accessible from the DDC system. This is for safety reasons since each room is
individually setup for maximum performance.
RPC30 Variable List
Integer DDC system receives
1 Room
1 Room with Anteroom
None
Exhaust
Exhaust / Supply / Temp
Room Status
Room Status and Pressure
All Measurements
1 second
2 seconds
3 seconds
5 seconds
10 seconds
20 seconds
40 seconds
in. W.C., cfm, F
Pa, lps, C
Pa, m
3
/hr., C
Off
Room Mode
Menus
Room Mode and Menus
High Alarm
Negative Room Mode
Positive Room Mode
TSI Sensor
Pressure Transducer
TSI Sensor
Pressure Transducer
Temperature Setpoint
None
Supply Pressure Flow
Supply Linear Flow
Supply Venturi
Supply Switch
None
Room 1 Door Switch
Room 1 Occupancy Sensor
None
Room 1 Key Switch
Relative Humidity
None