Orion System VCM-X Modular E-BUS - Manual (Page 66)

Zone
Zone
SEQUENCE OF OPERATIONS
VCM-X Modular E-BUS Controller Technical Guide 66
Scheduling and Internal Trend Logging
Scheduling
The VCM-X E-BUS Controller has an internal power source for the
Real Time Clock (RTC) that allows the controller to keep the time and
accurately control scheduling. It can also broadcast the time to the VAV/
Zone Controllers if that option is confi gured.
The VCM-X E-BUS Controller has an internal 7-day Schedule with 2
Start/Stop Events per day. You can also have 1 Holiday Schedule with
2 Start/Stop Events per day. This Holiday Schedule can be used for 14
different Holiday periods.
You can change the time on the VCM-X E-BUS Controller through the
Modular Service Tool, Modular System Manager, or the System Manager
TS II. You can also broadcast the time and date to all VCM-X E-BUS
Controllers by using a Personal Computer and the Prism Computer
Front-End Software.
The Internal Scheduling in the VCM-X E-BUS Controller also includes
a Self-Teaching Optimal Start Routine that can be activated by entering
a value of 1.0 or greater for the Soak Multiplier Setpoint. The Optimal
Start function can only be used if your VCM-X E-BUS Controller has a
Space Temperature Sensor installed and it is being used as the Control-
ling Sensor or if you are using WattMaster VAV/Zone controllers with
the VCM-X E-BUS Controller.
No adjustments other than the Soak Multiplier are required because
the VCM-X E-BUS Controller monitors how long it takes to reach the
Target Temperature each day and adjusts the Starting Time accordingly.
That means the fi rst day you operate your HVAC unit, it will not be able
to Optimally Start because it does not have a history of previous Starts
and their results. After the fi rst day, the VCM-X E-BUS Controller will
begin adjusting the Start Time, and after six Normally Scheduled Starts
have occurred, the Optimal Start Routine will have gathered enough
data to provide an accurate Pre-Start based on the learned conditions.
This is an ongoing learning process of the six previous starts, so the
unit automatically adjusts for the changing seasons. If you don’t need
this feature, but you are using the Space Temperature Sensor as the
Controlling Sensor, you can set the Soak Multiplier to zero to eliminate
the Optimal Start Routines.
Internal Trend Logging
The VCM-X E-BUS Controller continuously maintains an Internal
Trend Log, which records a fi xed set of values at a user-programmed
interval. These values can be retrieved only with the Prism Computer
Front-End Software. If you do not have a computer with Prism Software
installed and connected to the system communications loop, you do not
have access to these logs.
There are 120 log positions available. Once the last (120th) position
has been recorded, the log jumps back to the fi rst position and begins
overwriting the old data. This means the you will need to retrieve the
logs at an interval that is shorter than the duration of the last 120 logs
Shown below are some log intervals and the duration of 120 logs.
1 minute interval = 2 hours
12 minute interval = 24 hours
15 minute interval = 30 hours
30 minute interval = 60 hours
60 minute interval = 120 hours
The fi xed items in the log are listed below:
Date
Time
Mode (Status Bits)
Return Air Temperature
Outdoor Air Temperature
Supply Air Temperature
Supply Air Temperature Setpoint
Coil Suction Temperature
Outdoor Air Dewpoint
Indoor Air Humidity
Duct Static Pressure
Building Static Pressure
Economizer Signal Percentage
Supply Fan VFD/Zoning Bypass Damper Signal Percentage
Exhaust Fan VFD/Exhaust Damper Signal Percentage
Modulating Heat Signal Percentage
Modulating Cooling Signal Percentage
Space Temperature
On Board Relay Status (Bit Pattern)
Expansion Module Relay Status (Bit Pattern)
Head Pressure
Condenser Fan Signal Percentage
Outdoor Air CFM
Supply Air CFM
Return or Space CO
2
ModGas II Module Signal Percentage
Modulating Hot Gas Reheat II Module Signal Percentage
These items and values are explained in greater detail in the Prism 2
Computer Front-End Software Technical Guide.