West Control Solutions N6600 User Manual

1/8-DIN & 1/16-DIN

PLASTICS CONTROLLERS

Product Manual

PREFACE

This manual comprises two volumes:

Volume 1: This supports normal operation of the 1/8-DIN and 1/16-DIN

Plastics Controllers. In normal operation, all actions taken by
the user are to be in front of the front panel.

Volume 2: This supports the installation, commissioning and configuring of

the 1/8-DIN and 1/16-DIN Plastics Controllers. It is intended for
use only by personnel who are trained, equipped and
authorised to carry out these functions.

PM-0075

1

-DIN &

8

1

-DIN

16

PLASTICS CONTROLLERS

PRODUCT MANUAL

VOLUME 1

OPERATING INSTRUCTIONS

In normal operation, the operator must not remove the Controller from its housing
or have unrestricted access to the rear terminals, as this would provide potential
contact with hazardous live parts.

Installation and configuration must be undertaken by technically-competent
servicing personnel. This is covered in Volume 2 of this manual.

Contents - Volume 1

1 INTRODUCTION 1-1

1.1 TAILORING THE CONTROLLER TO SUIT YOUR NEEDS 1-2

1.2 HOW IT WORKS 1-3

2 OPERATOR MODE 2-1

2.1 INTRODUCTION 2-1

2.2 SELECTING THE PARAMETER TO BE DISPLAYED/ADJUSTED 2-1

2.3 ADJUSTING THE DISPLAYED PARAMETER 2-3

2.4 SOFT START 2-3

2.5 INDICATION OF AN ALARM GOING ACTIVE 2-4

2.6 ALARM STATUS DISPLAY 2-4

2.7 OVER-RANGE/UNDER-RANGE DISPLAYS 2-4

2.8 SENSOR BREAK INDICATION 2-5

2.9 OUTPUT TURN OFF 2-5

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2.10 MANUAL CONTROL MODE 2-5

2.11 HEATER CURRENT DISPLAY 2-5

2.12 SOFT START IN PROGRESS 2-6

2.13 QUICK TRANSFER OF HEATER CURRENT TO NOMINAL VALUE 2-6

2.14 PRE-TUNE 2-7

2.15 SELF-TUNE 2-7

2.16 TO VIEW THE HARDWARE DEFINITION CODE 2-8

3 SET UP MODE 3-1

3.1 ENTRY INTO SET UP MODE 3-1

3.2 SET UP MODE PARAMETERS 3-2

3.3 OPERATOR MODE DISPLAYS 3-17

3.4 TUNING THE CONTROLLER MANUALLY 3-18

3.5 SELF-TUNE 3-19

3.6 EXIT FROM SET UP MODE 3-20

4 MODBUS RTU COMMUNICATIONS 4-1

4.1 COMMUNICATIONS WRITE ENABLE/DISABLE 4-1

4.2 PHYSICAL REQUIREMENTS 4-1

4.3 MODBUS RTU PROTOCOL 4-1

4.4 INDIVIDUAL PARAMETERS 4-9

5 ASCII COMMUNICATIONS 5-1

5.1 COMMUNICATIONS WRITE ENABLE/DISABLE 5-1

5.2 PHYSICAL REQUIREMENTS 5-1

5.3 INDIVIDUAL PARAMETERS 5-7

5.4 ERROR RESPONSE 5-15

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1 INTRODUCTION

The

16

1

-DIN and

1

-DIN Plastics Controllers are economical, microprocessor-based

8

temperature controller specially designed for use in plastics applications. They
incorporate the latest in surface-mount and CMOS technology. The standard
features include:

• Dual four-digit LED display (upper display red, lower display green).

• Thermocouple or three-wire RTD sensor input

• Relay, SSR drive (10V) or solid state Output 1.

• Input range selected from the front panel.

• Heater current “ammeter” on front panel. Can use a unique two-wire

“SCRi” connection to dedicated silicon controlled rectifier stacks. Also
supports standard four-wire connection via a separate current
transformer.

• Heater Break alarms (high, low and short-circuit) to cater for most

requirements.

• Unique “Quick Transfer” for easy set up of heater break alarms. This can

be initiated from the front panel, digital input or via the communications
link

• Soft Start with dedicated setpoint, timer and Output 1 power limit.

• Adjustable alarm hysteresis.

• 90 - 264V AC power supply.

• Certified to EN50081-1:1992 and EN50081-2:1994 (Emission) and to

EN50082-1:1992 and EN50082-2:1995 (Immunity) EMC specifications.
Complies with EN61010-1:1993 Safety Standard.

• Front panel sealing to IP66 (NEMA 4) standard.

• CE rated (UL pending).

• Auto/Manual Control and Auto/Zero Power

• Pre-Tune and Self-Tune.

• Setpoint ramping.

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• Programmable input filter.

• Alarm type selected from front panel.

• Sensor Break protection.

• Setpoint maximum and minimum limits (user-defined).

and its many optional features include:

• MODBUS and ASCII (selectable) communications with up to 128 zone

address capability.

• Output 2 - secondary (COOL) control output (relay, SSR drive or solid

state), Alarm 2 output, Heater Break alarm output or logical combination
of Alarm 1 and Alarm 2.

• Output 3 - Alarm 1 output, Heater Break Alarm output, DC recorder output

(setpoint or process variable) or logical combination of Alarm 1 and
Alarm 2.

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• Output 4 - Heater Break Alarm output.

• Dual setpoint, remotely selectable.

NOTE: The communications option and the dual setpoint/quick
transfer option are mutually exclusive.

1.1 TAILORING THE CONTROLLER TO SUIT YOUR NEEDS

The Controller has three modes in which adjustments can be made via the front
panel keys:

Configuration Mode: This is normally used only when the Controller is
first configured or when a major change is to be made to the
Controller characteristics. Entry into this Mode is security-protected.
The Configuration Mode parameters should be set as required
before any other adjustments are made. Changing Configuration
Mode parameters invariably sets other parameters to their default
values. Adjustments to these parameters should be performed only
by personnel competent and authorised to do so.

Set Up Mode: This mode is used when a change to the process
set-up is required. The frequency of use for this mode is dependent
upon the process being controlled. This mode also determines the
scope of adjustments available in Operator Mode (see below).
Access to this mode is via a user-defined password.

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Operator Mode: This is the mode for day-to-day use. The parameters
in this mode are freely available to the operator. The adjustment
facilities available in this mode are dependent upon the settings of
parameters in the Set Up Mode.

1.2 HOW IT WORKS

The Plastics Controller is tailored towards plastics applications. The function of the
Controller is best described in terms of the control it exercises over the process
and the use of its alarms.

1.2.1 Control

The temperature at which the process must operate is called the setpoint (SP). The
actual process temperature which is being measured and controlled is called the
process variable (PV). Thus, if the setpoint is adjusted to 200 °C, the Controller
endeavours to maintain the process variable at 200°C.

PID control (also known as three-term control) is a well-proven and widely-used
method for high accuracy automatic control. Best results are obtained when the
Controller is correctly tuned - easily achieved by just letting the Controller tune
itself to your process, using the automatic tuning features.

Heater current is controlled via Output 1. Although the heater can only be either
fully-on or fully-off, the process reacts only to the average power, assuming heater
on-off periods are sufficiently brief. The PID algorithm can control average power
very accurately, thereby ensuring smooth and accurate control of the process.
This method of controlling output power is very common and is known as
time-proportioning. An adjustable Cycle Time parameter determines the duration
of each on-off output cycle. Longer cycle times prolong mechanical relay
contact life; shorter cycle times (normally using solid state relays) will be needed
on processes which react more quickly. Output 2 can be used as a cooling
output, if required.

The Controller has a special Soft Start feature, used when a gentle start-up phase
is required in order to avoid damage to the process. An adjustable Soft Start
Setpoint is used by the Controller during a Soft Start. The duration of the Soft Start
phase is determined by an adjustable Soft Start Time parameter. During this
phase, Ouput 1 power is kept within an adjustable limit and the Output 1 cycle
time is reduced to a quarter of its normal value (but never less than 0.5 seconds)
to reduce further the risk of thermal shock to the process.

The Controller can be put into Manual Control if selected by the operator. In this
mode, the operator adjusts manually the Controller’s output power. When
switching between automatic control and manual control, the Controller
minimises any sudden power changes; this is known as a “ bumpless transfer” and
avoids thermal shocks to the process. Manual Control mode can be configured to
be a non-adjustable zero power value or disabled completely.

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1.2.2 Alarms

Alarms allow early warning (and automatic corrective action, if necessary) in the
event of abnormal process conditions - heater failure, sensor failure, human error
etc. In addition to giving visual indication of such conditions, alarms can be
connected to outputs; the Controller can intervene automatically as soon as it
detects a problem in the plant.

Two standard alarms are provided which warn if the process variable temperature
moves outside prescribed limits. These alarms can be set to react if the process
variable goes above or below specific temperatures or moves too far away from
the setpoint. In the latter case, the alarm settings need no re-adjustment if the
setpoint is changed.

Heater break alarms allow prompt detection of heater failure, minimising the risk
of damage to the process. Three different types of alarm are provided, permitting
the majority of heater failures to be handled effectively. The actual heater current
can be displayed on the front panel.

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2 OPERATOR MODE

2.1 INTRODUCTION

This Section covers the routine operation of the Controller, once it has been
installed and configured. The Controller front panel indicators and keys are shown
in Figure 2-1.

Figure 2 -1 Front Panel Indicators and Control Keys

2.2 SELECTING THE PARAMETER TO BE DISPLAYED/ADJUSTED

After the Controller has performed its power-up self-test, the initial displays
appear. The Scroll key may then be used to step through the available displays.
These displays are dependent upon whether the Controller has been configured
for Single Setpoint operation or Dual Setpoint operation (see overleaf).

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NOTES

1. Setpoint is not adjustable if Setpoint Strategy = 1 (see Subsection 3.2.40)
but is adjustable if Setpoint Strategy = 2. Active setpoint is one of: Setpoint,
Setpoint 1, Setpoint 2 or Soft Start Setpoint, as appropriate.

2. Appears only if setpoint ramping is enabled and ramp rate is in the
range 1 - 9999.

3. Ramp rate is adjustable in the range 1 - 9999 (On) and Off (blank).

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NOTES (continued)

4. Only appears if a Soft Start is in progress; see Subsection 2.4.

5. Appears only if an alarm is active; see Subsection 2.6.

6. In dual setpoint operation, the lower display distinguishes between the
active and inactive setpoints in the following manner:

2.3 ADJUSTING THE DISPLAYED PARAMETER

If either of these keys is held down for 10 seconds or more, the adjustment rate
changes to “high speed” mode.

2.4 SOFT START

Soft Start is used when a gentle start-up phase is required, before going to full
working temperature. During Soft Start, a dedicated setpoint is used to control the
process to a lower temperature than normal. A power limit can be applied to
Output 1 during Soft Start, constraining the average Output 1 power. During Soft
Start, the Output 1 cycle time is automatically reduced to give added protection
against thermal shock (NOTE: because of the nature of time-proportioned outputs,
Output 1 will still be fully-on for part of each output cycle).

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Soft Start Time, Soft Start Setpoint and power limit are all adjustable in Set Up Mode
(see Section 3). Soft Start is aborted at start-up if the process variable exceeds the
Soft Start Setpoint. Setpoint ramping is inhibited during Soft Start. During a Soft
Start, the Soft Start time remaining at any moment may be read from the front
panel.

2.5 INDICATION OF AN ALARM GOING ACTIVE

If any of the Heater Break Alarms (High, Low or Short Circuit), Alarm 1 or Alarm 2
goes active, the HB/AL indicator will flash.

2.6 ALARM STATUS DISPLAY
(available if one or more alarms are active)

The alarm status display is in the following format:

2.7 OVER-RANGE/UNDER-RANGE DISPLAYS

If the process variable goes under-range or over-range, the upper display will
show the appropriate one of:

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2.8 SENSOR BREAK INDICATION

If a break is detected in the sensor circuit, the upper display will show:

The reaction of the outputs and alarms to a detected sensor break is dependent
upon the input type.

2.9 OUTPUT TURN OFF
(AM Key Usage Set Up parameter = )

Press the AM key to switch between automatic control and the control output(s)
being permanently turned off. A return to automatic control is via a bumpless
transfer. The SET indicator flashing pattern will be mostly OFF (if in Operator Mode)
or mostly ON (if in Set Up Mode).

2.10 MANUAL CONTROL MODE

(AM Key Usage Set Up parameter = )

Press the AM key to switch between manual control and automatic control. In
manual control, the output power is displayed and may be adjusted. The SET
indicator flashing pattern will be mostly OFF (if in Operator Mode) or mostly ON (if
in Set Up Mode).

Transfer between automatic control and manual control is bumpless in both
directions.

2.11 HEATER CURRENT DISPLAY

(AM Key Usage Set Up parameter = )

Press the AM key to display quickly the process variable/heater current,
regardless of the original display. The heater current display is in the format:

Press the AM key again to display the process variable/setpoint (i.e. the first
Operator Mode display). Subsequent AM key presses will switch between these
two displays.

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2.12 SOFT START IN PROGRESS

If a Soft Start is in progress, the heater current display will show (in the lower
display):

The normal heater current display will be restored as soon as the Soft Start time
has expired.

2.13 Q UICK TRANSFER OF HEATER CURRENT TO

NOMINAL VALUE

The nominal value of the heater current is manually adjustable in Set Up Mode.
However, to set the nominal value to the prevailing heater current value in
Operator Mode:

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2.14 PRE-TUNE

To tune approximately the Controller’s PID parameters, activate Pre-Tune:

The AT indicator will flash whilst Pre-Tune is operating. To dis-engage Pre-Tune,
repeat this procedure (the AT indicator will go OFF).

2.15 SELF-TUNE

To optimise tuning whilst the Controller is operating, activate Self-Tune:

To dis-engage Self-Tune, repeat this procedure (the AT indicator will go OFF).

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2.16 TO VIEW THE HARDWARE DEFINITION CODE

The Hardware Definition Code indicates the input type and output type(s) fitted
(see below). To view this Code:

The same key action causes a return to the normal Operator Mode display. An
automatic return is made to the normal Operator Mode display after 30 seconds.
The Hardware Definition Code has the following significance:

Value 0 1 2 3 4 5 7 8 9

Input

Output

1

Output
2( & 4)

Output

3

Not

fitted

Not

fitted

RTD

Input

Relay

Output

Relay

Output

2

Relay

Output

Thermo-

couple

Input

SSR

Drive

Output

SSR

Drive

Output

2

DC

0-10V

Output

DC

0-20mA

Output

DC

0-5V

Output

DC

4-20mA

Output

Solid
State

Output

Solid
State

Output

2

Solid
State

Output

Relay
Output
2 & 4 *

* Dual Relay Option PCB must be fitted

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3 SET UP MODE

3.1 ENTRY INTO SET UP MODE

NOTE: If the upper display shows:

(i.e. all decimal point positions ON), parameters are at their default values,
possibly due to a change in Controller configuration. To cancel this
indication, adjust any Set Up Mode parameter (see below). It is
recommended that all configuration parameters are finalised before any
adjustments are made to Set Up Mode parameters.

O075-3 3-1

3.2 SET UP MODE PARAMETERS

Table 3 -1 Set Up Parameters

Parameter Legend Adjustment Range Default

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Input Filter Time
Constant

Process Variable Offset

OFF, 0.5s to 100.0s In 0.5s
increments

±input span of Controller

2.0s

0
Output Power 0 to 100% Read Only
Output Power 2

4

0 to 100% Read Only
Proportional Band 1 0.0% to 999.9% of input span 10.0%
Proportional Band 2
Reset (Integral Time

Constant)

1

Rate (Derivative Time
Constant)

1

Overlap/Deadband

14,

14,

0.0% to 999.9% of input span 10.0%

1s to 99m 59s and OFF. 5m 00s

00s to 99m 59s 1m 15s

−20% to + 20% of Proportional

0%

Band 1 + Proportional Band 2
Manual Reset (Bias)

1

0% to 100% (single output)

25%

−100% to +100% (dual output)

ON/OFF Differential 2:

0.1% to 10% of input span 0.5%

Output 1 only

Output 2 only

Outputs 1 & 2

4

4

Setpoint High Limit Setpoint to Range Max. Range

Max.

Setpoint Low Limit Range Min. To Setpoint Range

Min.

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Table 3 -1 (Cont.) Set Up Parameters

Parameter Legend Adjustment Range Default

Recorder Output

−1999 to 9999

Range Max.

Scale Max.
Recorder Output

-1999 to 9999 Range Min.

Scale Min.
Output 1 Power Limit
Output 1 Cycle Time 0.5, 1, 2, 4, 8, 16, 32, 64, 128,

1

0 to 100% of full power 100%

32seconds

256 or 512 seconds

Output 2 Cycle Time 0.5, 1, 2, 4, 8, 16, 32, 64, 128,

32seconds

256 or 512 seconds

Process High Alarm 1
value

3

Process Low Alarm 1
value

3

Band Alarm 1 value
Deviation Alarm 1

value

3

3

Range Min. To Range Max. Range Max.

Range Min. To Range Max. Range Min.

0 to span from Setpoint 5 units
±span from Setpoint 5 units

Alarm 1 Hysteresis 1 - 250 units 1 unit
Process High Alarm 2

value

3

Process Low Alarm 2
value

3

Band Alarm 2 value
Deviation Alarm 2

value

3

3

Range Min. To Range Max. Range Max.

Range Min. To Range Max. Range Min.

0 to span from Setpoint 5 units
±span from Setpoint 5 units

Alarm 2 Hysteresis 1 - 250 units 1 unit
Heater Current High

ScaleLimit
Heater Current

Nominal

9

Low Heater Break
Alarm level (% or
amount below

10.0A to 20.0A in 0.1A steps
21A to 100A in 1A steps

0 to Heater Current High
Scale Limit

1% to 100% (of nominal) and
0 (OFF) or 0.1A/1A to Heater
Current High Scale Limit

50A

High Scale
Limit

20% or 0 (OFF)

nominal heater
current)

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Table 3-1 (Cont.) Set Up Parameters

Parameter Legend Adjustment Range Default

High Heater Break
Alarm level (% or
amount above

1% to 100% (of nominal) and 0
(OFF) or 0.1A/1A to Heater
Current High Scale Limit

0 (OFF)

nominal heater
current)

Short Circuit Heater
Break Alarm

10

0 (disabled) or 1 (enabled) 1 (enabled)

Soft Start Setpoint Range Min. To Range Max. Range Min.
Soft Start Time 15s to 59m 45s and 0 (OFF) in

0 (OFF)

15-second increments

Auto Pre-Tune

0 (disabled) or 1 (enabled) 0 (disabled)

Enable/Disable
AM Key Usage

Output Turn-off

Manual Control

Heater Current
display/Manual
Control Disable

SP Ramping

0 (disabled) or 1 (enabled) 0 (disabled)

Enable/Disable
Comms. Write

Enable/Disable

6

0 (disabled) or 1 (enabled) 1 (enabled)

Setpoint Strategy 1 or 2 1
Lock Value 0 to 9999 10

OPERATOR MODE DISPLAYS (still accessible in Set Up Mode)

PV/Active SP See Subsection 2.2 ­PV/Heater Current Read Only ­SP or SP1

8

SPHi to SPLo SPLo

SP2 (Dual SP only) SPHi to SPLo SPLo
Ramping SP value
SP Ramp Rate
Soft Start Time

5

7

Read Only ­1 to 9999 and OFF OFF
Read Only -

Remaining
Alarm Status Read Only (see Subsection 2.6)-

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NOTES ON TABLE 3-1

1. These parameters are not operative if the Proportional Band = 0.

2. Switching differential with ON/OFF Control Output.

3. These parameters are optional; only one legend will appear for each alarm.

4. Only applicable if Output 2 is fitted.

5. Appears only if ramp rate rp is not switched OFF.

6. Applicable only if the Communications Option PCB is fitted.

7. Does not appear in Operator Mode unless rPEN = 1.

8. For Single Setpoint operation, the legend displayed is SP ; for Dual Setpoint
operation, the legend displayed is SP1 .

9. Applicable only when Heater Break Alarm Strategy is configured to Percentage
Mode.

10. Does not appear if Heater Break Input Type is configured to be SCRi.

3.2.1 Input Filter Time Constant

The Controller input is equipped with a digital filter which is used to filter out any
extraneous impulses on the process variable. This filtered PV is used for all
PV-dependent functions (control, alarms etc.). The time constant for this filter may
be adjusted in the range 0.0 seconds (filter OFF) to 100.0 seconds in 0.5 second
increments. The default setting is 2.0 seconds.

CAUTION: If this parameter is set to an excessively high value, the control
quality may be significantly impaired. The value chosen should be
sufficiently large to attenuate stray noise on the process variable signal but
no larger.

3.2.2 Process Variable Offset

This parameter is used to modify the actual process variable value (measured at
the Controller’s input terminals) in the following manner:

Offset PV value = Actual PV value + Process Variable Offset value.

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The offset process variable value is used for all PV-dependent functions (control,
display, alarm, recorder output etc.).

NOTE: This parameter value should be chosen with care. Any
adjustment to this parameter is, in effect, a calibration adjustment.
Injudicious application of values to this parameter could lead to the
displayed process variable value bearing no meaningful
relationship to the actual process variable value. There is no front
panel indication when this parameter is in effect (i.e. has been set to
a non-zero value).

The default value is 0.

3.2.3 Output Power 1

This parameter is the current Output 1 power level. It is a “Read Only” parameter
and is not adjustable.

3.2.4 Output Power 2

This parameter is the current Output 2 power level (if Output 2 is fitted). It is a
“Read Only” parameter and is not adjustable. If Output 2 is not fitted, this
parameter display is not applicable.

3.2.5 Proportional Band 1

This parameter is the portion of the input span of the Controller over which the
Output 1 power level is proportional to the displayed process variable value. It
may be adjusted in the range 0.0% (i.e. ON/OFF control) to 999.9%. The default
value of this parameter is 10.0%. The function of the Proportional Band 1 is
illustrated in Figure 3-1.

3.2.6 Proportional Band 2

This parameter is the portion of the input span of the Controller over which the
Output 2 power level is proportional to the displayed process variable value. It
may be adjusted in the range 0.0% (i.e. ON/OFF control) to 999.9%. The default
value of this parameter is 10.0%. This parameter is applicable only if Output 2 is
fitted. In Figure 3-1, Proportional Band 2 is shown (a) with a non-zero value (Case 1
and Case 2) - PID control, and (b) with a zero value (Case 3) - ON/OFF control.

3.2.7 Reset ( Integral Time Constant)

This parameter is adjustable in the range 1 second to 99 minutes 59 seconds and
OFF (value greater than 99 minutes 59 seconds). This parameter is not applicable
if Proportional Band 1 (see Subsection 3.2.5) is set to 0 (ON/OFF control).

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Figure 3-1 Proportional Band and Deadband/Overlap

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3.2.8 Rate (Derivative Time Constant)

This parameter is adjustable in the range 00 seconds to 99 minutes 59 seconds.
This parameter is not applicable if Proportional Band 1 (see Subsection 3.2.5) is set
to 0 (ON/OFF control).

3.2.9 O verlap/Deadband

This defines the portion of the Proportional Band (Proportional Band 1 +
Proportional Band 2) over which both outputs are active (or, in the case of a
deadband, neither output is active). It is adjustable within the range –20% to
+20% (negative value = deadband). The default value is 0%. The function of the
overlap/deadband is illustrated in Figure 3-1. This parameter is not applicable if
Proportional Band 1 = 0 or if Output 2 is not fitted.

Note that, with Output 2 set to ON/OFF control (Figure 3-1 Case 3), the
Overlap/Deadband parameter has the effect of moving the ON Differential band
of Output 2 to create an overlap (positive values) or a deadband (negative
values). When Overlap/Deadband = 0, the “Output 2 OFF” edge of the Output 2
ON/OFF Differential band coincides with the point at which Output 1 reaches 0%.

3.2.10 Bias (Manual Reset)

This bias to the output power is expressed as a percentage of output power and is
adjustable in the range 0% to 100% (if only Output 1 is fitted) or –100% to +100%
(if both outputs are fitted). Its default value is 25%. This parameter is not
applicable if Proportional Band 1 = 0.

3.2.11 ON/OFF Differential ( Hysteresis)

This is a switching differential used when one or both outputs have been set to
ON/OFF control (i.e. Proportional Band 1 or Proportional Band 2 or both = 0). This
parameter may be adjusted within the range 0.1% to 10.0% of the input span of
the Controller. The default value is 0.5%.

3.2.12 Setpoint High Limit

This is the maximum limit for setpoint adjustment. It should be set to a value which
prevents the setpoint being given a value which will cause damage to the
process being controlled. The Setpoint High Limit may be adjusted between the
current setpoint value and Input Range Maximum. The default value is Input
Range Maximum.

3.2.13 Setpoint Low Limit

This is the minimum limit for setpoint adjustment. It should be set to a value which
prevents the setpoint being given a value which will cause damage to the

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process being controlled. The Setpoint Low Limit may be adjusted between the
Input Range Minimum and the current setpoint value. The default value is Input
Range Minimum.

3.2.14 Recorder Output Scale Maximum

This parameter defines the value of process variable or setpoint (whichever is
applicable) at which the Recorder Output reaches its maximum value; for
example, for a 0 - 5V Recorder Output, this value corresponds to 5V. It may be
adjusted within the range –1999 to 9999. The decimal point position for the
Recorder Output is always the same as that for the process variable input range.
The default value is Input Range Maximum. This parameter is not applicable if the
Recorder Output option is not fitted.

NOTE: If this parameter is set to a value less than that for the Recorder
Output Scale Minimum (see Subsection 3.2.15), the relationship between
the process variable/setpoint value and the Recorder Output is reversed.

3.2.15 Recorder Output Scale Minimum

This parameter defines the value of the process variable or setpoint (whichever is
applicable) at which the Recorder Output reaches its minimum value; for
example, for a 0 - 5V Recorder Output, this value corresponds to 0V. It may be
adjusted within the range –1999 to 9999. The decimal point position for the
Recorder Output is always the same as that for the process variable input range.
The default value is Input Range Minimum. This parameter is not applicable if the
Recorder Output option is not fitted.

NOTE: If this parameter is set to a value greater than that for the Recorder
Output Scale Maximum (see Subsection 3.2.14), the relationship between
the process variable value and the Recorder Output is reversed.

3.2.16 Output 1 Power Limit

This parameter is used to limit the power level of Output 1 and may be used to
protect the process being controlled. If no protection is required, this parameter
may be set to 100% (the default value). It may be adjusted between 0% and
100%. This parameter is not applicable if Proportional Band 1 is set to 0.

If Soft Start is used, this power limit is applicable ony during Soft Start. When Soft
Start is completed, Output 1 power can go to 100%.

3.2.17 Output 1 Cycle Time

The cycle time value required is dependent upon the process being controlled
and the type of output being used for Output 1. For a Relay Output, the cycle
time should be as large as possible (whilst remaining compatible with the process

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control requirements) in order to maximise relay life. For an SSR Drive Output, the
cycle time may have a lower value (and thus satisfy the requirements of a
fast-changing process variable e.g. flow or pressure). The permitted range of
values is:

0.5, 1, 2, 4, 8, 16, 32, 64, 128, 256 or 512 seconds

The default value is 32 seconds. This parameter is not applicable if Proportional
Band 1 is set to 0.

3.2.18 Output 2 Cycle Time

The cycle time value required is dependent upon the process being controlled
and the type of output being used for Output 2. For a Relay Output, the cycle
time should be as large as possible (whilst remaining compatible with the process
control requirements) in order to maximise relay life. For an SSR Output, the cycle
time may have a lower value (and thus satisfy the requirements of a fast-changing
process variable e.g. flow or pressure). The permitted range of values is:

0.5, 1, 2, 4, 8, 16, 32, 64, 128, 256 or 512 seconds

The default value is 32 seconds. This parameter is not applicable if Proportional
Band 1 or Proportional Band 2 is set to 0.

3.2.19 Process High Alarm 1 Value

This parameter, applicable only when Alarm 1 is selected to be a Process High
alarm, defines the process variable value at or above which Alarm 1 will be
active. Its value may be adjusted between Input Range Maximum and Input
Range Minimum. Its default value is Input Range Maximum. The operation of a
process high alarm is illustrated in Figure 3-2.

3.2.20 Process Low Alarm 1 Value

This parameter, applicable only when Alarm 1 is selected to be a Process Low
alarm, defines the process variable value at or below which Alarm 1 will be
active. Its value may be adjusted between Input Range Maximum and Input
Range Minimum. Its default value is Input Range Minimum. The operation of a
process low alarm is illustrated in Figure 3-2.

3.2.21 Band Alarm 1 Value

This parameter, applicable only if Alarm 1 is selected to be a Band Alarm, defines
a band of process variable values, centred on the setpoint value. If the process
variable value is outside this band, the alarm will be active. This parameter may
be adjusted to be within ±(input span) from the setpoint. The default value is five
input units. The operation of a band alarm is illustrated in Figure 3-2.

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Figure 3-2 Alarm Operation

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3.2.22 Deviation (High/Low) Alarm 1 Value

This parameter, applicable only if Alarm 1 is selected to be a Deviation High/Low
Alarm, defines a value above (positive value - Deviation High alarm) or below
(negative value - Deviation Low alarm) the setpoint; if the process variable
deviates from the setpoint by a margin greater than that defined by this
parameter, Alarm 1 goes active. This parameter value may be adjusted in the
range ± (input range) from setpoint. The default value is five input range units. The
operation of Deviation Alarms is illustrated in Figure 3-2.

3.2.23 Alarm 1 Hysteresis

This parameter applies a hysteresis band on the “safe” side of the Alarm 1 value.
Thus, Alarm 1 will become active when the Alarm 1 value is exceeded; Alarm 1
will become inactive when the process variable value is outside the hysteresis
band on the “safe” side of the Alarm 1 value. Alarm 1 Hysteresis may be set to a
value in the range 1 - 250 or 0.1 - 25.0 (as per input resolution). The effect of the
hysteresis value on the operation of the different types of alarm is illustrated in
Figure 3-3.

3.2.24 Process High Alarm 2 Value

This parameter, applicable only when Alarm 2 is selected to be a Process High
alarm, defines the process variable value at or above which Alarm 2 will be
active. Its value may be adjusted between Input Range Maximum and Input
Range Minimum. Its default value is Input Range Maximum. The operation of a
process high alarm is illustrated in Figure 3-2.

3.2.25 Process Low Alarm 2 Value

This parameter, applicable only when Alarm 2 is selected to be a Process Low
alarm, defines the process variable value at or below which Alarm 2 will be
active. Its value may be adjusted between Input Range Maximum and Input
Range Minimum. Its default value is Input Range Minimum. The operation of a
process low alarm is illustrated in Figure 3-2.

3.2.26 Band Alarm 2 Value

This parameter, applicable only if Alarm 2 is selected to be a Band Alarm, defines
a band of process variable values, centred on the setpoint value. If the process
variable value is outside this band, the alarm will be active. This parameter may
be adjusted to be within ±(input span) from the setpoint. The default value is five
input units. The operation of a band alarm is illustrated in Figure 3-2.

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Figure 3-3 Alarm Hysteresis Operation

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3.2.27 Deviation (High/Low) Alarm 2 Value

This parameter, applicable only if Alarm 2 is selected to be a Deviation High/Low
Alarm, defines a value above (positive value - Deviation High alarm) or below
(negative value - Deviation Low alarm) the setpoint; if the process variable
deviates from the setpoint by a margin greater than that defined by this
parameter, Alarm 2 goes active. This parameter value may be adjusted in the
range ± (input range) from setpoint. The default value is five input range units. The
operation of Deviation Alarms is illustrated in Figure 3-2.

3.2.28 Alarm 2 Hysteresis

This parameter applies a hysteresis band on the “safe” •side of the Alarm 2 value.
Thus, Alarm 2 will become active when the Alarm 2 value is exceeded; Alarm 2
will become inactive when the process variable value is outside the hysteresis
band on the “safe” side of the Alarm 2 value. Alarm 2 Hysteresis may be set to a
value in the range 1 - 250 or 0.1 - 25.0 (as per input resolution). The effect of the
hysteresis value on the operation of the different types of alarm is illustrated in
Figure 3-3.

3.2.29 Heater Current High •Scale Limit

This parameter defines the full scale value for the heater current range. It may be
adjusted from 10.0A to 20.0A in 0.1A increments, and then from 21A to 100A in 1A
increments. The default value is 50A. Heater current range minimum is fixed at
0A. This value also determines the Short Circuit Heater Break Alarm level (see
below).

NOTE: If this parameter value is changed, the Heater Nominal Current, Low
Heater Break Alarm Value and High Heater Break Alarm Value parameters
are set to their default values (see Table 3-1).

3.2.30 Heater Nominal Current

This parameter defines a nominal value for the heater current and is only
applicable if Heater Break Alarm Strategy is configured to Percentage Mode. It
may be adjusted in the range 0A to Heater Current High Scale Limit. The default
value is the Heater Current High Scale Limit. It can also be set automatically (in
Operator Mode or Set Up Mode) to the heater current value at any instant by
using “Quick Transfer” (see Subsection 2.13).

3.2.31 Low Heater Break Alarm Value

The Controller monitors two current values: ON-current (when Output 1 is on) and
OFF-current (when Output 1 is off). This parameter defines a heater ON-current
value below which the Low Heater Break Alarm will become active. It may be
adjusted in the following ranges below the heater current nominal value:

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