CDK ELECTRONICS DC68K User manual

CDK ELECTRONICS LTD
DC68K Pack Control
USER MANUAL
V1.1a
Copyright 2001, CDK Electronics Ltd, 17/19, Buxton Road, Congleton, Cheshire
All Rights Reserved.
This document is supplied in confidence for use only in the design, production, maintenance and operation of
CDK Electronics’ Ltd equipment and must not be used for any other purpose. It may not be copied or its
contents divulged without written consent from CDK Electronics Ltd. The information contained within this
document is believed to be correct on the date of issue. CDK Electronics Ltd reserves the right to change
features and/or specifications without prior notice. No responsibility can be accepted by CDK Electronics Ltd
for the misuse of the information contained in this document.

Page
CDK Electronics Ltd, 17/19, Buxton Road, Congleton, Cheshire. CW12 2DW.
Tel 01260 296300. Fax 01260 296301.
www.cdk.co.uk
2
DC68K Pack Controller - Issue 1.1a - Sept 2001
This page is intentionally blank.

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CDK Electronics Ltd, 17/19, Buxton Road, Congleton, Cheshire. CW12 2DW.
Tel 01260 296300. Fax 01260 296301.
www.cdk.co.uk
3
DC68K Pack Controller - Issue 1.1a - Sept 2001
INTRODUCTION .......................................................................................................................................... 4
NORMAL RUNNING.................................................................................................................................... 5
High Pressure Override. .............................................................................................................................. 5
LP Pressure Override................................................................................................................................... 5
SYSTEM BACKUP & FAILURE MODES. ................................................................................................ 6
INSTALLATION ........................................................................................................................................... 7
Wiring........................................................................................................................................................... 7
Power supply ................................................................................................................................................ 7
Communications Network Connections........................................................................................................ 8
Communications Address. ............................................................................................................................ 9
CONFIGURING THE SYSTEM ................................................................................................................ 10
Programming the DC68K........................................................................................................................... 10
System Configuration. ................................................................................................................................ 10
Adjusting the Control Settings.................................................................................................................... 12
CONTROL SETTINGS............................................................................................................................... 13
DEFAULT CONTROL SETTINGS........................................................................................................... 16
FINE TUNING THE SYSTEM................................................................................................................... 17
SYSTEM STATUS ....................................................................................................................................... 18
SPECIFICATIONS. ..................................................................................................................................... 19
Technical. ................................................................................................................................................... 19
LIST OF FIGURES...................................................................................................................................... 20
USER MANUAL ISSUE UPDATES. ......................................................................................................... 21

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CDK Electronics Ltd, 17/19, Buxton Road, Congleton, Cheshire. CW12 2DW.
Tel 01260 296300. Fax 01260 296301.
www.cdk.co.uk
4
DC68K Pack Controller - Issue 1.1a - Sept 2001
INTRODUCTION
The DC68K Pack Controller (referred to as the DC68K in this manual) provides control
for both suction and discharge of up to four packs (i.e. two LT and two HT packs)
An LCD display and keypad enable settings to be programmed and current status to be
viewed. Control is affected via RS485 serial communications from the DC68K to remote
serial I/O units (PACK-IO boards) A second RS485 serial communications port is
provided for communications to a Storescan III alarm panel, this link is required for
floating the suction pressures. For information on programming the DC68K from the
Storescan please consult the Storescan manuals.
The PACK-IO boards will relinquish control to the mechanical backup in the event of a
power/communication fault to the DC68K pack controller.
DC68K
PACK
CONTROLLER
DC PACK
I/O
DC PACK
I/O
DC PACK
I/O
DC PACK
I/O
LT1 SUCTION
LT1 DISCHARGE
HT1 SUCTION
HT1 DISCHARGE
DC PACK
I/O
DC PACK
I/O
DC PACK
I/O
DC PACK
I/O
LT2 SUCTION
LT2 DISCHARGE
HT2 SUCTION
HT2 DISCHARGE
RS485
STORESCAN III
RS485

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Tel 01260 296300. Fax 01260 296301.
www.cdk.co.uk
5
DC68K Pack Controller - Issue 1.1a - Sept 2001
NORMAL RUNNING
The DC68K provides two control methods, “Sequence mode” and “Intelligent mode”.
•Sequence mode - output stages are stepped on and off sequentially beginning
with output stage 1, i.e. first on - last off.
•Intelligent mode - stages are switched on and off after a series of calculations
based on, stage capacity required, minimum off and minimum on times and
start per hour restrictions.
The DC68K system controls the suction and discharge pressures by comparing the control
pressure from each PACK-IO with the programmed setpoint and deadband. Calculations
are then made based upon the pressure difference, control and differential gain, stages
available and stages required, the remote outputs are then switched appropriately.
Override setpoints are provided to control excessive pressure swings at both low and high
pressures.
High Pressure Override.
If the pressure rises above the “HP Override” setpoint and remains above for more than 5
seconds. All the programmed outputs will be switched at 10-second intervals. Normal
control will be resumed as soon as the pressure falls below the override setpoint.
LP Pressure Override.
If the control pressure falls below the “LP Override” setpoint. All stages will be switched
off. Normal control will be resumed as soon as the pressure rises above the override
setpoint.

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CDK Electronics Ltd, 17/19, Buxton Road, Congleton, Cheshire. CW12 2DW.
Tel 01260 296300. Fax 01260 296301.
www.cdk.co.uk
6
DC68K Pack Controller - Issue 1.1a - Sept 2001
SYSTEM BACKUP & FAILURE MODES.
If the DC68K is connected to a Storescan III system, a copy of the configuration is held
within the Storescan, this enables the control settings to be adjusted from the Storescan,
and the settings to be backed up. However it is important to note that the Storescan must
be put into program mode before any adjustments are made within the DC68K. Failure to
do so will mean that the Storescan will restore the original settings the next time they
communicate.
Note:
Setting adjustments must be accepted at the Storescan or the original settings will
be restored.
If communications between the DC86K and PACK-IO’s are lost, then a four and a half
minute timer is started and during this period no stages are turned off or on. If
communications have not been re-established before this timer has elapsed, then all stages
will drop out allowing the mechanical backup to take control. At this point the alarm relay
on the PACK-IO will drop out.
If power is lost to a PACK-IO then all stages will drop out, allowing the mechanical
backup to take control. At this point the alarm relay on the PACK-IO will also drop out.

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CDK Electronics Ltd, 17/19, Buxton Road, Congleton, Cheshire. CW12 2DW.
Tel 01260 296300. Fax 01260 296301.
www.cdk.co.uk
7
DC68K Pack Controller - Issue 1.1a - Sept 2001
INSTALLATION
SAFETY WARNING - 230vac is present on the internal circuits, software / hardware
(mechanical or electrical/electronic) system failures have no disconnection functionality; it
must therefore be assumed that all working voltages are permanently present.
ISOLATE THE CONTROLLER IF CARRYING OUT WORK OTHER
THAN SYSTEM SETTINGS OR ADJUSTMENTS.
WORK ON LIVE CIRCUITS MUST ONLY BE CARRIED OUT BY
TRAINED COMPETENT ENGINEERS.
Wiring.
The DC68K Pack Controller is intended for use in stores using PACK-IO boards and the
Storescan III system with serial RS485 communication links to control suction and
discharge loads.
The wiring to serial modules and associated control panels should be arranged in
such a manner as to keep the interaction with other equipment through electromagnetic
coupling to a minimum, guidelines for field wiring are listed below: -
9Segregate low voltage cables, mains feed cables and 3 phase motor cables from each
other, ideally in separate trunking or looms.
9Low voltage and high voltage cables should only cross at right angles.
9Keep wiring as short as possible.
9Fit suppressors to contact coils.
9All screened cable should be connected to earth at one end only.
8No signal circuit should run parallel to an unscreened motor circuit or unfiltered
supply cable with spacing less than 0.3m and over a distance not exceeding 1m. For
runs exceeding 10m, the spacing should increase in proportion to the run. For example
for a run of 40m paralleled the spacing should be 0.3 x 40 /10 = 1.2m.
Power supply
The DC68K requires a 230vac supply capable of supplying 1 amp @ 50Hz.
See Figure 1 for “Wiring Details”.

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CDK Electronics Ltd, 17/19, Buxton Road, Congleton, Cheshire. CW12 2DW.
Tel 01260 296300. Fax 01260 296301.
www.cdk.co.uk
8
DC68K Pack Controller - Issue 1.1a - Sept 2001
Communications Network Connections.
There are two RS485 communication networks connected to a DC68K, an internal
network connected to the PACK-IO controllers and an external network to the Storescan
III.
Note:
These two networks are incompatible and must not be connected to each other.
9Ensure the correct cable (BELDEN 8762 or equivalent) is available.
9When stripping the cable, remove about 25mm of outer PVC and peel the
screening foil back to the outer PVC, cut off the screening foil. The white
or clear insulated conductor is 'A', the black insulated conductor is 'B' and
the non-insulated drain wire is the screen. Strip about 5mm of insulation
from the 'A' and 'B' conductors. All but the end of run serial unit require
both an in and an out cable wired into the same terminals. Twist the
appropriate conductors together before fitting to the orange plug. Ensure
the wires are in the correct position.
9Only 30 serial units are permitted to share each of the communication
cables (the DC68K counts as 1 unit per run).
8DO NOT: Run power cables in the same tray or trunking as
communications cable.
8DO NOT: Connect the cable screen to earth. (The connection is pre-made
inside the Storescan III panel).
CPU Board mounted
on rear of door
RS485 network to Storescan III
RS485 network to PACK-IO boards

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CDK Electronics Ltd, 17/19, Buxton Road, Congleton, Cheshire. CW12 2DW.
Tel 01260 296300. Fax 01260 296301.
www.cdk.co.uk
9
DC68K Pack Controller - Issue 1.1a - Sept 2001
Communications Address.
The network address in the DC68K is set using the two rotary switches, these being set in
hex i.e. C8 on the rotary switches corresponding to address 200 (top switch set to ‘8’ and
the bottom switch set to ‘C). This is the address that Storescan will use to establish
communications.
HEX DEC HEX DEC
0 0 10 16
1 1 20 32
2 2 30 48
3 3 40 64
4 4 50 80
5 5 60 96
6 6 70 112
7 7 80 128
8 8 90 144
9 9 A0 160
A 10 B0 176
B 11 C0 192
C 12 D0 208
D 13 E0 224
E 14 F0 240
F 15
Note:
The DIL switch has no function and is reserved for future use.
The network addresses in the PACK-IO’s are set using an 8-way dipswitch on each
controller. Valid addresses are from 1 to 32. Only switches 1 through 6 are recognized for
address settings. Addressing is achieved using a binary code dipswitch setting
(1,2,4,8,16,32); the board address will be the sum of all switch values in the ‘ON’
position. For example, to set an address of ‘3’ switches 1 and 2 should be set ON, and
switches 3,4,5,6 should be set OFF.
Binary conversion table
Switch number Binary value
1 1
2 2
3 4
4 8
5 16
6 32
Dipswitch 7 is used to set the number of transducers .
Dipswitch 8 is used to set the pressure range of the transducers.
Note:
If any Dipswitch setting is changed then the PACK-IO will need to be reset by
removing the power.
Switch 7
ON 2 Transducers
OFF 1 Transducer
Switch 8
ON HP Transducer
OFF LP Transducer

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CDK Electronics Ltd, 17/19, Buxton Road, Congleton, Cheshire. CW12 2DW.
Tel 01260 296300. Fax 01260 296301.
www.cdk.co.uk
10
DC68K Pack Controller - Issue 1.1a - Sept 2001
CONFIGURING THE SYSTEM
Programming the DC68K.
To access the menu screens press the ‘E’
or enter key, use the up or down arrows to
view the options, pressing the ‘E’ key will
select the option, pressing the ‘C’ key or
cancel will discard any changes to the
current screen and return to the status
screen.
The settings screens are split in to distinct
areas: -
•System Settings - select this option to
set the addresses of the PACK-IO’s
connected to the system.
System Configuration.
After selecting the system option from the
menu screen, the user is prompted for the
address for “Pack 1 Suction”. The system
will display “1” as a default. To change
the address press the up arrow to
increment the number and the down arrow
to decrement the number, press the enter
key to accept the change. The option
display will now show ‘Pack 1 Discharge
Address”, adjust the setting if required
and press enter. The next screens will
display the setup options for packs 2, 3
and 4.
Note:
Any addresses entered here must be
the same as the addresses that the
PACK-IO controllers are set to use.
P a c k
S Y S T E M
P a c k 1 S u c t A d d r
1
P a c k 1 D i s A d d r
2

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11
DC68K Pack Controller - Issue 1.1a - Sept 2001
Pack n- Each of the four packs can be
selected in turn. Select the required
pack and then any of the options listed
below. The suction and discharge
options are used to set the normal
control settings and the Pressure
offsets are used to calibrate the
transducer readings.
Note:
The offsets are measured in counts
not Psi or Bar, they are scaled 0 to
20, 10 being no offset.
•Pack nSuction
•Pack nDischarge
•Pack nSuction Offset
•Pack nDischarge Offset
•Pack nSuction Capacities
•Pack nSuction Unloaders
•Pack nSuction Starts Per Hr
Suction Capacities:
This allows different sized compressors to
be programmed.
Suction Unloaders:
This allows the programming of
unloading stages into the system.
Starts Per Hour:
Specifies the maximum starts per hour for
each compressor.
Device List –
This option is only intended for use by
CDK engineers. The pack settings screens
will overwrite any changes that are made
from this screen.
P a c k
1
P a c k 1
S u c P r e s s O f f s e t
P a c k 1
D i s c h a r g e
P a c k 1
S u c t i o n
P a c k 1
D i s P r e s s O f f s e t
P a c k
D e v i c e L i s t
P a c k 1
S u c C a p a c i t i e s
P a c k 1
S u c S t a r t P e r H r
P a c k 1
S u c U n l o a d e r s

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CDK Electronics Ltd, 17/19, Buxton Road, Congleton, Cheshire. CW12 2DW.
Tel 01260 296300. Fax 01260 296301.
www.cdk.co.uk
12
DC68K Pack Controller - Issue 1.1a - Sept 2001
Adjusting the Control Settings.
Select a pack from the menu options, and
select the suction or discharge option by
pressing the “Enter” key. Each of the
available settings are displayed in turn,
use the directional keys to adjust the
setting and the “Enter” key to confirm the
adjustment and move on to the next
setting.
Each setting can be increased or decreased
by using the up and down arrows. Using
the left and right arrows the cursor can be
moved under the hundreds, tens or units
figures, the up and down arrows will then
increment in steps of 10 or 100.
Note that some settings screens display
two figures, the number in brackets is the
actual pressure reading and the other
number is system counts. When making
changes the system counts are modified
and the pressure displayed will change
accordingly.
S e t p o i n t P S I
23 ( 1 0 )
Actual pressure
displayed in PSI
Adjust this figure to
change the pressure
setting.

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Tel 01260 296300. Fax 01260 296301.
www.cdk.co.uk
13
DC68K Pack Controller - Issue 1.1a - Sept 2001
CONTROL SETTINGS
The control settings for each of the packs are accessed in sequence, through each pack
menu option. A list of all the different settings and there function is shown below: -
SETPOINT.
The setpoint specifies the target pressure for the system; it can be
adjusted across the whole range of the transducer. Typically the
suction range is 0-100PSI and discharge 0-500PSI.
DEADBAND.
The deadband is symmetrical around the setpoint and specifies a
pressure band in which control calculations are no longer
preformed. The system will recalculate the control requirements as
the pressure leaves the deadband. Typical settings for the deadband
would be 5PSI for LT suction, 10PSI for HT suction and 4PSI for
the discharge control, the value can be adjusted across the whole
pressure range of the transducer.
GAIN.
The control or proportional gain setting adjusts the response of the
controller to the changes in pressure. The gain can be adjusted from
1 to 100, the larger the number the faster the system responds to the
pressure change. The default value is 6 for suction control and 30
for the discharge control.
DIFF GAIN.
The differential gain setting allows the system to react to sharp rises
and falls in pressure, a larger gain will result in a faster response to
a rapid change. This setting can be adjusted from 1 to 100; typical
values are LT suction 4, HT suction 7 and discharge 8.
LP SHUTDOWN.
The low-pressure shut down setting specifies a pressure at which all
stages will be turned off, once the pressure climbs above this
setting, normal control is resumed. The setting is adjustable across
the whole pressure range.
HP OVERRIDE.
The high-pressure override setting specifies the pressure at which
all stages are turned on in an attempt to reduce the pressure as
quickly as possible. Note that for LP controllers there is a 10 second
interval between stages turning on, and a 1 second delay for HP
controllers. The setting is adjustable across the whole pressure
range.

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Tel 01260 296300. Fax 01260 296301.
www.cdk.co.uk
14
DC68K Pack Controller - Issue 1.1a - Sept 2001
MIN UP TIME.
The minimum up time specifies the time that must elapse before a
stage can be turned on. Note that the delay is not used if the current
pressure is below the LP Shutdown setpoint or above the HP
Override setpoint. The default time is 10 seconds; the setting can be
adjusted from 10 second to 255 seconds, but must be less than the
maximum time setting.
MAX UP TIME.
The maximum time specifies the time that can elapse before a stage
will be turned on, this setting is used to set the control range, the
shorter the time the quicker the system will respond to any pressure
change, a typical value for the LT suction control is 40 seconds, 120
seconds for the HT suction control, 30 seconds for the LT discharge
control and 40 seconds for the HP discharge. The adjustable range
is from 10 to 255 seconds, but must be greater than the minimum
time.
MIN DOWN TIME.
The minimum up time specifies the time that must elapse before a
stage can be turned off. Note that the delay is not used if the current
pressure is below the LP Shutdown setpoint or above the HP
Override setpoint. The default time is 10 seconds; the setting can be
adjusted from 1 second to 255 seconds, but must be less than the
maximum time setting.
MAX DOWN TIME.
The maximum time specifies the time that can elapse before a stage
will be turned off, this setting is used to set the control range, the
shorter the time the quicker the system will respond to any pressure
change, a typical value for the LT suction control is 40 seconds, 120
seconds for the HT suction control, 30 seconds for the LT discharge
control and 40 seconds for the HP discharge. The adjustable range
is from 10 to 255 seconds, but must be greater than the minimum
time.
MIN ON TIME.
The minimum on time specifies the minimum time that a
compressor will run for before it can be switched off. The range is
from 1 to 255 minutes.
MIN OFF TIME.
The minimum off time specifies the minimum time that a
compressor will remain stopped for once it has been switched off.
The range is from 1 to 255 minutes.

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15
DC68K Pack Controller - Issue 1.1a - Sept 2001
NO OF STAGES.
This specifies the number of control stages connected to the
controller. The range is from 1 to 15.
START MODE.
The start mode setting specifies the starting strategy in use. Setting
a value of 1 will enable the controller to use any available stage as
required, whereas setting a value of 0 will force the controller to
start stages in a sequential order regardless of stage capacities.
FLOAT ENABLE.
This setting controls whether a Storescan II/III can adjust the pack
setpoints remotely. This is used to allow energy savings to be made,
depending on the status of the cases on the shopfloor. A setting of 0
disables this function; a setting of 1 enables this function.
RUN INPUT ENABLE.
This setting controls the ability of the controller to monitor the run
inputs attached to the controller. It operates in conjunction with the
Run Verify Time setting. A value of 1 will enable the run inputs,
and a value of 0 will disable the run inputs.
RUN VERIFY TIME.
This timer controls the delay between a compressor starting and the
controller receiving a run input. If the delay is set to 10 seconds and
a signal is not received within this time, then the compressor will be
assumed to be unavailable and the next available stage will be
started.
SMOOTHING
The smoothing enable setting determines whether the damping and
differential gain functions are enabled. Set the value to 1 to enable
smoothing.
DAMPING
The damping factor allows the system to calculate the differential
gain response times, and although the setting is currently adjustable,
it is recommended that the setting not be adjusted and left at 10.

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Tel 01260 296300. Fax 01260 296301.
www.cdk.co.uk
16
DC68K Pack Controller - Issue 1.1a - Sept 2001
DEFAULT CONTROL SETTINGS.
The following table gives suggested initial values at initial power up of the unit, these are
used for the initial control of the packs, and they can of course be configured as required.
DC68K Pack Controller Default MIN MAX Unit Comment
Pack 1 (LT) 2 (HT) 3 (LT) 4 (HT)
Suction
Setpoint 8 48 8 48 Psi Optimum control pressure
Deadband 2 3 2 3 Psi Symmetrical around the setpoint
Gain 5 8 5 8 Sys Increases Sensitivity
Diff Gain 4 1 4 1 Sys Controls Fast Pressure Changes
LP Shutdown 1 20 1 20 Psi Emergency Shutdown Setpoint
HP Override 20 70 20 70 Psi Emergency Override Setpoint
Min Up Time 10 15 10 15 Sec Min Time Between Loading Stages
Max Up Time 80 225 80 225 Sec Max Time Between Loading Stages
Min Down Time 10 5 10 5 Sec Min Time Between Unloading Stages
Max Down Time 80 80 80 80 Sec Max Time Between Unloading Stages
Min On Time 0 0 0 0 Sec Minimum Run Time Once Started
Min Off Time 0 0 0 0 Sec Minimum Stop Times Once Stopped
No Of Stages A/R A/R A/R A/R Qty The Number Of Output Stages
Start Mode 1 1 1 1 0/1 0 - Sequential 1 - Intelligent
Float Enable 0 1 0 1 0/1 Suction Optimisation (1 – Enable)
Run Input Enable 0 8 0 8 0/1 Use Run Signals (1 – Enabled)
Run Verify Time 10 1 10 1 Sec Time From Start to Receipt of Signal
Smoothing 1 10 1 10 0/1 Enables damping and Diff Gain
Damping 10 1 10 1 Sys System Setting. Do Not Adjust
Discharge 1 (LT) 2 (H10T) 3 (LT) 4 (HT)
Setpoint 161 165 161 165 Psi Optimum control pressure
Deadband 6 4 6 4 Psi Symmetrical around the setpoint
Gain 30 50 30 50 Sys Increases Sensitivity
Diff Gain 1 1 1 1 Sys Controls Fast Pressure Changes
LP Override 0 100 0 100 Psi Emergency Shutdown Setpoint
HP Override 251 270 251 270 Psi Emergency Override Setpoint
Min Up Time 10 15 10 15 Sec Min Time Between Loading Stages
Max Up Time 30 70 30 70 Sec Max Time Between Loading Stages
Min Down Time 5 10 5 10 Sec Min Time Between Unloading Stages
Max Down Time 30 50 30 50 Sec Max Time Between Unloading Stages
Min On Time 0 0 0 0 Sec Minimum Run Time Once Started
Min Off Time 0 0 0 0 Sec Minimum Stop Times Once Stopped
No Of Stages A/R 5 A/R 5 Qty The Number Of Output Stages
Run Input Enable 0 0 0 0 0/1 Use Run Signals (1 – Enabled)
Run Verify Timer 10 10 10 10 Sec Time From Start to Receipt of Signal
Smoothing 0 0 0 0 0/1 Enables damping and Diff Gain
Damping 10 10 10 10 Sys System Setting. Do Not Adjust

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CDK Electronics Ltd, 17/19, Buxton Road, Congleton, Cheshire. CW12 2DW.
Tel 01260 296300. Fax 01260 296301.
www.cdk.co.uk
17
DC68K Pack Controller - Issue 1.1a - Sept 2001
FINE TUNING THE SYSTEM.
There is no hard and fast method of setting up a controller to control a pack without
modifying the settings over a period of time. It is important to realize that all the settings
have a interaction with each other, for example increasing the maximum time will
decrease the effect that the gain setting has on the control of the pressure. As a general rule
the following guidelines should assist in setting the control values to somewhere near
optimum, further adjustments can only be made after monitoring the system performance.
•Set the ‘Differential Gain’ to 1, (the differential gain will have no
effect).
•Set the ‘Minimum Time’ to 10 seconds, (the minimum time can be
described as the delay between stages if the required output was
100%)
•Set the ‘Maximum Time’ from 40 - 120 seconds, (if the pressure sat
at 1 PSI above the setpoint, the maximum time would be the delay
before a stage was turned on).
•To determine the value for the gain setting, firstly choose the
preferred control band, (the relative pressure above the setpoint at
which the system should call for 100% or minimum time). Divide
the transducers pressure range, (i.e. 0-100 PSI transducer’s full
scale is 100) by the preferred control band. Set the gain to this
figure.
•Set the ‘Dead Band’ to 1/2 of the control band.
•The DC68K should then be left to control the pack for about 10 to
15 minutes so that the system can stabilize with the new settings.
Large pressure swings should be ignored at this point, just the
general reaction to normal pressure changes. If the stages are
switching on and off too quickly, try either extending the maximum
time by 10 seconds or reducing the gain setting by 1, if however the
system does not seem to control quickly enough, try either
decreasing the maximum time by 10 seconds or adding 1 to the gain
setting.
•Set the ‘Differential Gain’ to 5, (the differential gain will effect the
quick pressure changes). The more volatile the pressure changes
then the higher the differential gain should be set. Again the system
should left to run for 10 to 15 minutes to establish the true effect of
the differential gain before any changes are made.
In conclusion, the control settings are application specific, each pack and site will be
different. However, similar setups will require similar settings.

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CDK Electronics Ltd, 17/19, Buxton Road, Congleton, Cheshire. CW12 2DW.
Tel 01260 296300. Fax 01260 296301.
www.cdk.co.uk
18
DC68K Pack Controller - Issue 1.1a - Sept 2001
SYSTEMSTATUS
The current status of all the configured
packs can be viewed on the status screen,
if the status screen is not currently
displayed then press the ‘C’ or cancel.
The status screen displays both the
suction and discharge pressures along
with the current output expressed as a
percentage, ((100/No of stages)*stages
on).
Use the up and down arrow keys to scroll
through all 4 packs.
P 1 S 4 3 6 0 %
P 1 D 1 5 8 1 0 0 %
Actual Pressure
Output Percentage
Current Pack
S = Suction
D = Discharge

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CDK Electronics Ltd, 17/19, Buxton Road, Congleton, Cheshire. CW12 2DW.
Tel 01260 296300. Fax 01260 296301.
www.cdk.co.uk
19
DC68K Pack Controller - Issue 1.1a - Sept 2001
SPECIFICATIONS.
Technical.
IP20 Steel enclosure.
Supply Voltage: 230VAC 1A 50Hz
RS485 serial networking connections
2 x 16 character LCD display output
8 key touch panel
Software / hardware (mechanical or electrical/electronic) system failures have no
disconnection functionality; it must therefore be assumed that all working voltages
are permanently present.

Page
CDK Electronics Ltd, 17/19, Buxton Road, Congleton, Cheshire. CW12 2DW.
Tel 01260 296300. Fax 01260 296301.
www.cdk.co.uk
20
DC68K Pack Controller - Issue 1.1a - Sept 2001
LISTOFFIGURES
Figure 1 General Wiring Details
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