AKCESS System Manual RC.IU.B1.22 4/99.1 6-1
Chapter 6 Configuring and Using Non-AKCESS Nodes
The AKCESS system has the ability to interface with a number of Echelon-equipped non-AKCESS
devices. These are:
EMON energy monitors
Bitzer variable speed compressors
VLT
®
variable frequency drives for controlling speed of AC motors
Square D electronically controlled lighting panels.
Chapter 6 - 1 Echelon-capable Utility Meters
An AKCESS system can monitor Danfoss-approved energy meters which have an Echelon interface.
Each AKC 55 can monitor up to five meters. Each current source must have a dedicated meter.
Installation After installing the energy meter and current transformers according to instructions provided by their
manufacturer, the meter is connected to the AKCESS I/O network and becomes a node on the network
after configuration. Only one of the meters connected to an AKC 55 can be used for demand limiting.
Configuration To begin configuration of utility meters, select Energy from the main menu, then Utility Meter, then
Configure. You will be asked for the number of utility meters to be configured. After entering a
number, that number of meter names will appear, each with a Setup button. The default names are
“Meter #1,” “Meter #2,” etc. You can change the names as you would any other text field in the AKC
55. When you select the Setup button, then Board & Points, then Locate, the following screen
appears:
You have ninety seconds to press the service pin at the utility meter. The service pin is a small push-
button usually located on the main circuit board of the meter. Consult the meter instructions for its exact
location if it is not immediately apparent. If the meter is located at some distance from the AKC 55 or
PC you are using for configuration, you should arrange to communicate with a colleague stationed at the
meter for this operation.
After the service pin is pressed, you must wait the remainder of the ninety second period before further
action.
Pressing the service pin on the meter causes configuration information to be sent to the AKC 55. The
information received from the utility meter is the number of CT
6 - 2 System Manual RC.IU.B1.22 4/99.1 AKCESS
After you have been notified that a valid service pin message has been received, you should initialize the
utility meter node by selecting its Init field and pressing Enter.
Using Utility Meter
Status Screens To view current energy usage information, select Energy from the main menu, then Utility Meter, and
Meter Status, then select the meter name, and a meter status report appears:
The meter status screen fields show:
(1) the total KWH consumption since initialization (or since last reset via the service screen);
sets, amperage, and voltage. Although you can change these in the Meter Setup screen, the settings
must match the setup in the meter for correct functioning. When a valid service pin message has been
received by the AKC 55, a confirming message box will appear on the screen. If not, an “Operation
Failed” message appears at the bottom of the screen as shown here:
Remember that
when you initialize
the utility meter,
it will be reset.
Any accumulated
data will be lost !
AKCESS System Manual RC.IU.B1.22 4/99.1 6-3
Peak and KWH can be reset from the service screen, which is reached by using the service icon (in the
center) at the bottom of the screen. Both the AKC 55 and the utility meter counters will be reset.
History for
Utility Meters
Setting up and retrieving history for utility meters is much the same as for other datapoints. To configure
history of a meter, from the Main Menu select History, Configure History, and Setup History
Datapoints. This is the screen that appears:
Move the cursor to the fifth icon (a large “O” symbolizing “Other Controllers” and click. When the next
menu appears, select Utility Meter, then select a specific meter:
(2) the current load in KW for the service being metered;
(3) the peak KW since initialization (or since the last reset via the service screen);
(4) the date and time of the last reset for peak;
(5) the date and time of the last KWH reset
[Items 6, 7, and 8 appear ONLY if Demand Limiting has been configured. See the section on demand
limiting for further discussion.]
(6) KW average in window: the average in the demand window. This number is an estimate of the
peak for the window if load conditions continue as they are at present. The average is re-
calculated each minute.
(7) Level: the current demand limiting level. For demand limiting, HVAC units and lighting
zones can be assigned levels from 0 to 11. Loads are shed and restored according to
levels specified during demand limiting configuration. [See the section on demand limiting
for further explanation].
(8) The current load expressed as a percentage of the specified maximum load.
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When you click on a meter, the points available for history are shown:
AKCESS System Manual RC.IU.B1.22 4/99.1 6-5
Retrieving history produces this typical display:
Demand Limiting [When reading this section, it will be useful to review the part of the previous section, “Echelon-capable
Utility Meters, which describes the Meter Status Screen and the meanings of its fields.]
One utility meter per AKC 55 will allow configuration for demand limiting. Configuring demand limiting
strategy is a two-step process. First you select the meter to be used for demand limiting and enter the
parameters; then select the loads to be shed for limiting demand and give each a priority.
In order to use demand limiting, you must have a Danfoss-approved utility meter with Echelon interface
and, if you are going to establish both normal and emergency load limits, you must wire and configure an
on/off input for the automatic transfer switch. In addition, if the site has a coupling switch, you must
wire and configure an on/off input for the coupling switch.
To begin setting up a demand limiting strategy, start at the utility meter configuration screen. From the
main menu, select Energy, then Utility Meter, and Configure; then select the Setup button for the
meter to be used for demand limiting, then select Meter Setup.
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The contents of the demand limiting fields are as follows:
Window size The window width is set to 15, 20, or 30 minutes. Every
minute, the window “slides” forward so that it always contains
the most recent period of time. Each minute the accumulated
KW during that minute is recorded.
Normal load (for each
hour of the day) Enter the upper demand limit you do not wish to exceed for the
given hour of the day under normal operating conditions (when
using normal power).
Moving to the third page of the screen:
AKCESS System Manual RC.IU.B1.22 4/99.1 6-7
Maximum
emergency load Enter the upper demand limit you do not wish to exceed when
the emergency generator is running.
Start shedding at Enter the percent of maximum load at which you want to start
shedding loads.
Start restoring at Enter the percent of maximum load at which you want to start
restoring loads which have been shed.
Enable coupling switch In installations where there are two transformers and/or two
emergency generators, a coupling switch can be used to connect
both loads to one source in case the other source fails.
Number of normal steps The number of steps (levels) which you will allow to be shed
under normal conditions.
Number of emergency
steps The number of steps (levels) which you will allow to be shed
when the emergency generator is running.
Soft start begin level This entry specifies the level down to which loads will be turned
on when the emergency generator starts. A level will be added
each minute unless the specified emergency load for shedding to
start is reached.
The effect of a soft start is to slowly add load to the generator after it starts. If for instance soft start
begin level is set to 6, when the generator starts only refrigeration loads and loads assigned level 7
through 11 will be on. After one minute, if the load is below the “start shedding at” percentage of
maximum emergency load, level 6 will be turned on. After another minute, the same decision will be
made for level 5, and so on down to level one. If at any time the load reaches the “start shedding at”
percentage, load shedding will begin again until the system reaches the “start restoring at” percentage.
Now return to the Energy menu and select Demand Limiting, then Configure. On the Demand
Limiting Menu, there are two items: Select Units (for HVAC) and Select Zones (for lighting). Choose
Select Units and this screen appears:
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Note that the names of the HVAC units appear in the left-most column. If these units had not been
given names during configuration, then “Unit 1,” “Unit 2,” etc. would have appeared. For each HVAC
unit, make the following entries:
Unit The address of the AKC 55 which has the demand meter that
will be used for demand limiting. This can be any AKC 55 in the
network that has a meter configured for demand limiting.
Level The priority for shedding under normal conditions. Levels are
shed in ascending order: level 1, then level 2, and so on up to the
highest level configured, limited by the number of steps allowed.
Levels above the number of steps configured will not be shed
unless the meter configuration is changed. Since there are only
up to ten steps, loads assigned level 11 will never be shed. It is
recommended that loads which are not to be shed are left at level
11, the default value.
Emergency level The priority for shedding when the emergency generator is
running.
If a load is assigned level 0 (zero) for either normal or emergency conditions, the load will never come on
under those conditions.
For lighting zones, the screen entries are the same, except that each relay will have its own level.
How Demand
Limiting Works Utility demand is monitored every minute. Every minute, the most recent n minutes are averaged (where
n is the width of the configured window, 15, 20, or 30 minutes). If the average reaches the configured
“start shedding at” percentage of configured maximum demand, step one (all lighting zones and HVAC
units assigned to level 1) will be turned off. After one minute, when the average is calculated again, if the
demand is still above the configured percentage of configured maximum demand, level two will be shed,
and so on.
When demand has dropped to the “start restoring at” level, the last level shed will be restored, and then
the others in descending order, so that the last load restored will be the one which was shed first.
Restoration will continue as long as the load remains below the “start shedding at” percentage.
AKCESS System Manual RC.IU.B1.22 4/99.1 6-9
As soon as “Bitzer” has been selected as the proof type for the compressor, another question appears:
Reset Bitzer with RO? A yes answer to this question generates a relay output point. If
you wire the relay output point to terminal A7 on the Bitzer
interface board (labeled “Remote Alarm Reset”), you will be able
to use the RO to manually reset the Bitzer compressor if it is in
an alarm shutdown condition.
The next step in configuration is to go to the Rack Configuration screen for Board & Points, then Other
Controllers, and then select Bitzer. The resulting screen has a >Locate< button for each Bitzer
compressor configured.
After you click on a >Locate< button, you have 90 seconds to go to the Bitzer interface module for that
compressor and press the service pin or button. You must press the service button until the service LED
on the module illuminates and remains lit. Communication is established between the Bitzer module and
the AKC 55, which then assigns an address to the module. Note that addresses are reserved as follows:
1-8 for suction group 1, 9-16 for suction group 2, 17-24 for suction group 3, and so on. (Remember that
an AKC 55 can have up to 5 suction groups, and each one can have up to 8 compressors.)
After ninety seconds, if the Bitzer interface module has responded, a new message will display on the
AKC 55 screen, including the Bitzer module’s address.
Chapter 6 - 2 Bitzer Screw Compressor Echelon Interface
An AKC 55 can monitor Bitzer compressors that have an Echelon interface. Since an AKC 55 supports
up to 5 suction groups, each with up to 8 compressors, as many as 40 Bitzer interfaces are possible.
Bitzer Configuration
Configuration of a Bitzer Screw Compressor Interface begins when the Proof type is selected
for the compressor.
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In the example shown, the Bitzer Interface Module has supplied an address of 17, indicating that it is the
first Bitzer compressor in the third suction group configured in this AKC 55.
Compressor Status
and Bitzer Status The compressor status screen for a Bitzer compressor has the same structure and information as the
status screen for any other compressor. But by clicking on the compressor icon, an additional screen
appears, unique to compressors controlled with Bitzer interface modules. The screen looks like this:
AKCESS System Manual RC.IU.B1.22 4/99.1 6-11
The items shown as “Normal” in the screen shown above correspond to the Bitzer alarms discussed
below.
Alarms
Alarms for the Bitzer interface are configured in an AKC 55 by selecting the Bitzer icon from the
Configure Rack Alarms menu. All that is necessary is to set the alarms to the level required (None, Log
only, Normal, or Critical), since the time and level parameters are set by the Bitzer interface. The
alarm configuration screen shows the eight alarms each Bitzer interface can generate:
The meanings of these alarms as given in Bitzer literature are as follows:
Dirty oil filter Not a shut down function. A pressure differential switch built
into the oil filter has detected a 10 psi differential across the
filter.
Motor overload A shut down function. This alarm, which pertains only to semi-
hermetic screw compressors, occurs if compressor motor
windings overheat. A manual reset using the AKC 55’s Bitzer
reset RO is effective if the compressor is manually locked out.
Alternatively, the compressor can be configured to reset
automatically when the motor temperature is again within safe
limits. Consult Bitzer documentation for more information.
Oil flow This alarm condition will result in a shutdown after three
automatic resets. The alarm occurs when an oil flow switch built
into the compressor senses insufficient oil flow, insufficient
differential oil pressure, or both, for more than five seconds. If
the compressor has been configured for manual lockout, it can be
reset using the AKC 55’s Bitzer reset RO. Alternatively, the
compressor can be configured to reset automatically. Consult
Bitzer documentation for more information.
Oil level A shut down function. The oil level in the compressor’s oil
separator is below the safe operating range. Where parallel
compressors with Bitzer control modules are used, all compres-
sors in parallel will be manually locked out. Oil level alarms can
6-12 System Manual RC.IU.B1.22 4/99.1 AKCESS
only be reset automatically by the Bitzer control module after oil
level has returned to the safe operating range. The AKC 55’s
Bitzer reset RO will have no effect on compressors locked
out by oil level alarms.
Discharge temp A shut down function. Discharge temperature has exceeded
212 °F. A manual reset using the AKC 55’s Bitzer reset RO is
effective if the compressor is manually locked out. Alterna-
tively, the compressor can be configured to reset automatically
when the discharge temperature is again within safe limits.
Consult Bitzer documentation for more information.
Phase fail A shut down function. One or more of the three power legs
supplying the compressor has been interrupted, or is connected
improperly. The Bitzer interface will make three attempts to re-
start the compressor at thirty second intervals, then two
additional attempts at five minute intervals before entering a
permanent shutdown condition. The AKC 55’s Bitzer reset
RO will have no effect on compressors locked out by phase
fail alarms.
Rotation fail A shut down function. Compressor rotation has occurred in the
wrong direction. The alarm can be reset using the AKC 55’s
Bitzer reset RO.
Run proof fail A compressor has not responded when being asked to run by the
controller. The alarm can be reset using the AKC 55’s Bitzer
reset RO.
Resetting Shutdowns
with the Bitzer Reset RO
In order to reset a shutdown compressor, manually the Bitzer reset RO must be turned on, then
turned off.
That reset RO has
to be turned on
and off again to
reset a shutdown
Bitzer
compressor !!
AKCESS System Manual RC.IU.B1.22 4/99.1 6-13
Chapter 6 - 3 VLT
®
Electronic Drive Interface
An AKC 55 can control and monitor Danfoss VLT
®
electronic drives that have an Echelon interface.
Each AKC 55 can support a maximum of one VLT
®
per compressor, one per condenser group, and one
per AHU. In the following section, we’ll discuss these applications one by one.
VLT
®
Configuration
for Compressors
Configuration of a VLT for variable speed compressor control begins when inverter control is selected on
the configuration screen for a compressor. Normally there is only one variable speed compressor in a
suction group, and conventionally it is compressor number one. Here’s the configuration screen for
compressor 1 of a suction group:
For the field Inverter control there are three selections: NONE, VO, and VLT
®
. After VLT
®
is
selected as the type of control, the settings for inverter operation (minimum speed, maximum speed,
etc.) are entered.
VLT
®
Resets, Proof,
and Faults The example screen shown above contains the default values, which should be changed only by a
knowledgeable technician.
When a VLT
®
first begins to run (time = r), fault-checking occurs constantly (every 1-3 seconds). If a
fault is detected, the VLT
®
is reset.
Inverter max resets is the number of resets which can accumulate in the reset counter (a space in the
AKC 55’s memory) before the VLT
®
is placed in bypass. The reset counter is cleared whenever no
resets have occurred in the past 12 hours. In the case of the unit whose screen is shown above, if the
reset counter = 3, a reset will place the unit into bypass mode.
If at time = (r + proof delay) there is no proof signal, the VLT
®
is put directly into bypass mode by the
AKC 55 (see below under Inverter Status).
Continuing Configuration Now go to the Configure Rack screen and select Board & Points, then select the far right icon at the
bottom of the screen (a big “O” for “Other”), then select VLT
®
from the Other Controllers menu.
Once that selection is made, this screen appears:
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Select Locate for the VLT
®
you are configuring (in this example, the first one listed, which is for compres
sor AA1). Now this screen appears:
You have 30 seconds to press the VLT
®
service pin. Depending on the distance from the AKC 55 to the
VLT
®
, you may need to have a colleague standing by at the VLT
®
and in communication with you for
this procedure.
When the service pin is pressed, if the VLT
®
is properly connected to the I/O network, after about 90
seconds this message will appear on the AKC 55:
AKCESS System Manual RC.IU.B1.22 4/99.1 6-15
Now the VLT
®
is completely configured. Simply press any numeral (digit) key as the message says.
Note that it is not necessary to go to rescan the network for new nodes when you configure a device that
has a service pin. The service pin operation serves the same purpose for its node.
VLT
®
Status Screens
for Compressors Compressors with VLT
®
variable speed drives have a VLT button on their status screen, which looks like
this:
Inverter Status The number shown in the Inverter field is the percent of whatever maximum motor speed was entered
during configuration. The Inverter field can also have other contents, which are as follows:
Bypass on No Proof: There is no proof signal from the VLT
®
to the AKC 55, and so
the VLT
®
has been placed in bypass mode. The compressor is
operating as a fixed speed compressor.
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Off The AKC 55 refrigeration function is not calling for the
compressor to run.
Resetting The VLT
®
is being reset. This message will appear for a period
of time equal to the reset delay.
Bypass on Fault The VLT
®
has reported a fault in its operation and has been
placed in bypass mode. The compressor is operating as a fixed
speed compressor.
Bypass on No Proof The AKC 55 is calling for the VLT
®
to run, but no proof signal is
being received
In the lower left corner of the screen body is a VLT button. Select it, and you will see the VLT
Status screen:
The screen above shows an inverter in normal operation. Field contents and meanings are as follows:
No Fault Normal operation. The drive is not in bypass.
Fault The drive, due to improper operation, has been put into bypass
mode. The compressor will operate at 100% speed whenever it
is turned on by the AKC 55 refrigeration function, which will
not consider the compressor as a variable speed compressor.
No Warning Normal operation.
Warning Warning messages are sent to the AKC 55 from the VLT
®
; there
are six types of warning, but the type is not sent to the AKC 55
since the warnings are VLT
®
functions. The type of warning
can only be determined from the display on the VLT
®
display.
For a full description of VLT
®
warnings, see the VLT
®
manual.
Running The inverter proof condition is true. This means that the variable speed compressor is needed
for refrigeration and the AKC 55 senses that the VLT
®
is sending the compressor current. This
condition can only change if the compressor is taken out of AKC 55 control, at the VLT
®
keypad if the
drive is changed from Auto to Manual mode (see below), or if the VLT
®
is in bypass.
AKCESS System Manual RC.IU.B1.22 4/99.1 6-17
Not Running There is no proof. The AKC 55 does not sense that the VLT
®
is
sending the compressor current.
Auto The VLT
®
is being controlled by the AKC 55. This condition
can only be changed at the VLT
®
keypad.
Manual The VLT
®
has been taken out of AKC 55 control. This change
can only be made at the VLT
®
keypad.
VLT
®
’s and Air-
Cooled Condensers
Configuration Configuration of a VLT
®
for use with an air-cooled condenser is very similar to the configuration
described above for refrigeration compressors. In the first page of the Configure Rack Condensers
screen, Control method must be set to Target. In the second page of the samescreen, set Fan Inverter
Control to VLT. Then variable speed settings are entered as for refrigeration compressors.
Bypass on Pressure In addition to other error messages described in the section on use of VLT
®
’s with refrigeration compres-
sors, VLT
®
’s used with air-cooled condensers have another bypass message, which is Bypass on
Pressure. The maximum head pressure specified in configuration has been reached, and the VLT
®
has
been placed in bypass. All condenser fans will run continuously to reduce the head pressure.
VLT
®
’s and Air
Handler Motors
Configuration A VLT
®
can be used to control the speed of air handler fans wherever RTC rooftop controller boards are
not being used. It is first necessary, during configuration, to select Variable VLT as the fan type.
Maximum and minimum fan speeds and inverter settings are similar to those described above for other
loads. The last two settings on this screen determine the leaving air temperatures at which fan speed is
increased for cooling and for dehumidification. Leaving air temperature is measured by sensors placed on
the cooling coils. Normally the ramp up temperature for dehumidification is lower so that when
dehumidification is needed, the fan will run slower (will not be speeded up until the temperature is
lower) so that the air stream will pass more slowly over the coils and more moisture will be removed.
6-18 System Manual RC.IU.B1.22 4/99.1 AKCESS
Now click on >Setup< to begin Powerlink
®
configuration.
Chapter 6 - 4 Square D Powerlink
®
Circuit Breaker Panels
An AKC 55 can control and monitor Square D Powerlink
®
circuit breaker panels that have an Echelon
interface. Each AKC 55 can support a maximum of five Powerlink
®
panels. Each Powerlink
®
panel can
have up to 42 breakers, each of which is considered equivalent to one lighting zone relay.
Powerlink
®
Configuration
Configuration of a Powerlink
®
begins after you have entered a number other that 0 in answering the
question “No. of Powerlink Panels?” on the Configure Lighting Zones screen:
AKCESS System Manual RC.IU.B1.22 4/99.1 6-19
The zone name can be changed to any of a list of 33 common lighting zones, or to a user defined name
(the second line on the screen shown above only appears if “User Def.” is selected on the first line.
The number of control points is analogous to the number of relays given for conventional lighting
points. It is the number of controllable groups into which the lights with this name are divided.
Configure each lighting point in turn by starting at the Configure Lighting Zones menu, choosing the type
of control (either PWRLK or AKC 55), then going to >Setup<.
Now go to the Configure Lighting menu and click on Board & Points. Using the icon menu at the
bottom of the screen, click on the right-most icon which resembles a Square D logo. The screen that
appears looks like this:
The panel names (shown by default as “Powerlink #1, Powerlink #2, etc.”) can be edited to match the
names of the actual panels in the store.
Continuing Configuration
Select Locate for the Powerlink
®
you are configuring (for example, the first one listed). Now this screen
appears:
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Now the Powerlink
®
location is complete. Simply press any numeral (digit) key as the message says.
Note that it is not necessary to rescan the network for new nodes when you configure a device that has a
service pin. The service pin operation serves the same purpose for its node.
You have 30 seconds to press the Powerlink
®
service pin. Depending on the distance from the AKC 55
to the Powerlink
®
, you may need to have a colleague standing by at the Powerlink
®
and in communica-
tion with you for this procedure. Consult the Powerlink
®
literature to locate the service pin.
When the service pin is pressed, if the Powerlink
®
panel is properly connected to the I/O network, after
about 90 seconds this message will appear on the AKC 55:
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