PPI Zenex Plus User Manual

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Zenex Plus User Manual

Zenex Plus

Multi-Purpose Temperature Controller

with Graphic Display

User Manual

Zenex Plus User Manual

CONTENTS

1. FRONT PANEL LAYOUT 1

2. BASIC OPERATION 2

3. OPERATOR PARAMETERS 5

4. SUPERVISORY PARAMETERS 7

5. FACTORY PARAMETER 12

6. PANEL MOUNTING AND ELECTRICAL CONNECTIONS 21

Zenex Plus User Manual

Section 1

FRONT PANEL LAYOUT

The Controller front panel comprises of Graphic Readout and Membrane Keys as shown in Figure 1.1 below.

Figure 1.1

PPI

Graphic

Readout

Zenex Plus

GRAPHIC READOUT

The Graphic Readout is a X Pixel Monochrome LCD Display. In Normal operation mode the Readout shows 128 64 measured Temperature Value, Set Temperature Value, Alarm / Process Status & Balance Time (if enabled & running). The Process Status Information can be viewed using screen scroll feature.

In Mode, the Readout displays parameter names and values that can be edited using front keys.Set-up

KEYS

There are six tactile keys provided on the front panel for configuring the and setting-up the parameter values. controller

The Table 1. below lists each key (identified by the front panel symbol) and the associated function. 1

Symbol

Key

25.8

TEMP HIGH

0:10:00

Table 1.1

°C

Keys

25.0

Function

Scroll

Alarm

Acknowledge

DOWN

SET-UP

ENTER

Press to scroll through various Process Information Screens in Normal Operation Mode.

Press to acknowledge and mute (if active) alarm output.

Press to decrease the parameter value. Pressing once decreases the value by one count; keeping pressed speeds up the change.

Press to increase the parameter value. Pressing once increases the value by one count; keeping pressed speeds up the change.

Press to enter or exit set-up mode.

Press to store the set parameter value and to scroll to the next parameter.

Zenex Plus User Manual

Section 2

BASIC OPERATIONS

Figure 2.1

POWER-UP DISPLAY

Upon power-up the controller displays model name, Hardware Version and Software Version for 2 seconds as shown in figure 2.1.

H/W Version

S/W Version

RUN MODE

After the Power-up display the controller enters into RUN Mode. This is the normal operation mode wherein the controller starts PV measurements, Alarm monitoring and Control Loop execution.

Main Screen

This is the default screen and its appearance depends upon whether a timer function is enabled or disabled as shown in the figures 2.2 (a) & 2.2 (b) respectively.

Figure 2.2(a) : Timer Disabled

Measured Temperature

Alarm / Process

Status

25.0

TEMP HIGH

°C

25.0

Set Temperature

Figure 2.2(b) : Timer Enabled

Note : The Balance Time is shown in either HHH:MM or H:MM:SS

depending upon the remaining time counts as under : HHH:MM for 249:59 to 10:00 H:MM:SS for 9:59:59 to 0:00:00

Balance Time

In case of measured value errors, the messages listed in Table 2.1 flash in place of process value as illustrated in Figure 2.3.

Table 2.1

Message Error Type

OPEN

OVR

UNR

Sensor Open

Over-range

Under-range

RTD Pt100 / Thermocouple is Broken / Open

Temperature above Max. Specified Range

Temperature below Min. Specified Range

Cause

0:10:00

25.0

TEMP HIGH

25.0

TEMP HIGH

°C

Figure 2.3

OPEN

Measured Temperature

Alarm / Process Status

Set Temperature

°C

25.0

Zenex Plus User Manual

The Alarm / Process Status space on the screen may show one or more of the several messages listed in Table 2.2 depending upon the existence of active alarms or process events. In case of co-existence of multiple active alarms or process events, the messages are scrolled one after the other with an approximate time interval of 3 seconds. Also if there is no active alarm or process event, the message space is blank.

Table 2.2

Message String Alarm / Process Status

Temp High

Temp Low

Tuning

Door Open

Timer Hold

Process Status Screen

The Process Status Screen is shown upon pressing (Scroll) key from Main Screen or upon acknowledging a new Alarm by pressing (Acknowledge) key. As depicted in Figure 2.4(a) for Old Version & 2.4(b) for New Version; the screen shows Temperature Alarm Status, Door Open / Close Status, the Heater Output Status (ON / OFF or % Power) & Compressor ON / OFF Status.

The measured temperature is in Process High Alarm State.

The measured temperature is in Process Low Alarm State.

The Controller is Self Tuning.

The Equipment / Chamber door is open for a time longer than the set ‘DOOR ALRM DLY’ time.

The Countdown Timer is paused since the PV is outside Hold Band.

Figure 2.4(a) :

Old Version

Temperature Alarm Status

Heating Control

Output Power

Temperature Alarm Status

Heating Control

Output Power

PROCESS STATUS

°C

High

Heating

0.0%

Figure 2.4(b) :

New Version

Process Status

Temp

High

Heater

0.0%

Compressor

Door

Compressor

OFF

Door

OFF

Door Status

Compressor

Output Status

Door Status

Compressor

Output Status

Zenex Plus User Manual

Figure 2.5 (a)

Temperature Alarm Status

Temp

Normal

Temp

Low

Temp

High

Within

Limits

Below

Low Limit

Above

High Limit

Figure 2.5 (b)

Door Status

Door

Open

The Controller provides programmable Low & High deviation limits around the temperature control setpoint to monitor Alarm conditions. The screen shows either Normal or Low or High Status, as shown in Figure 2.5 (a) depending upon the deviation of measured temperature value from the control setpoint and set limits.

The Controller provides a Digital Input for interfacing Door switch that senses the door position, Open or Close. The screen indicates the door status as shown in Figure 2.5 (b).

Zenex Plus User Manual

Section 3

OPERATOR PARAMETERS

The Operator Parameters are accessible under PASSWORD 0. The list includes parameters for adjusting Control Setpoint, Alarm Setpoints & Zero-offset. If Timer is enabled then Time Interval value & Timer Start / Abort commands are also available.

The Figure 3.1 shows how to access Operator Parameters. The Example illustrates changing the Low Deviation alarm value from 2.0 to 5.0. (The Example is shown with Timer disabled).

Figure 3.1

ENTER PASSWORD >>

2.0

°C

25.0

Press SET-UP Key for Password Entry

Press UP/DOWN Keys

to adjust Parameter Value

Default Password

for Operator Parameters

Press ENTER Key

To open Operator

LO DEVIATION >>

5.0

Desired Value

Press ENTER Key

to store the New Value

25.0

TEMP HIGH

RUN Mode

Main Screen

LO DEVIATION >>

Desired Parameter

& to move to Next Parameter

The Table 3.1 below described the Operator Parameters in detail.

Table 3.1

Parameter Description

Parameter List

CTRL SET VALUE >>

25.0

First Parameter

Press & Release

ENTER Key until Desired

Parameter appears

HI DEVIATION >>

2.0

Next Parameter

Settings

(Default Value)

TIME START COMMAND >> TIME ABORT COMMAND >>

(Available only if Timer is Enabled)

These two commands are mutually exclusive.

Set to Yes to start Timer, if not already started.

Set to Yes to abort a running timer.

TIME INTERVAL (H:M) >>

(Available only if Timer is Enabled)

The set time value for the timer in Hours : Minutes.

Yes

(Default : No)

0.01 to 249.59 (HH:MM)

(Default : 0.10)

Zenex Plus User Manual

Parameter Description

CTRL SET VALUE >>

This parameter sets the value at which the controller atte to mpts maintain the measured temperature value.

LO DEVIATION >>

This Parameter sets a negative deviation (offset) limit with respect to the ‘ ’. The Alarm is activated if the measured Control Set-point temperature value falls below this limit.

HI DEVIATION >>

This Parameter sets a negative deviation (offset) limit with respect to the ‘Control Set-point’. The Alarm is activated if the measured temperature value exceeds this limit.

CHANGE PASSWORD >>

The Controller is shipped from the factory with a default password (0) for accessing the parameters reserved for Operator. However, if required the password can be changed by setting the new value for this parameter.

(The new password replaces the old password. That is, the old password is no longer valid. it is user’s responsibility to memorize the password.)

Settings

(Default Value)

Setpoint LO limit to

Setpoint HI limit

(Default : 25.0)

0.2 to 99.9

(Default : 2.0)

0.2 to 99.9

(Default : 2.0)

1 to 100

(Default : 0)

Zenex Plus User Manual

Section 4

SUPERVISORY PARAMETERS

The various parameters have been assembled in different groups under the default factory password 123.

Refer Table 4.1 below for a quick summary of parameters under different groups. Each parameter has been described in subsequent sections.

Table 4.1

Group

Serial Parameter

Sensor Input

Device ID, Baud Rate, Parity, Serial Write

Zero Offset

Parameters

Tune, Setpoint Low Limit, Setpoint High Limit, Compressor Set-point, Compressor Hysteresis,

Control

Heat Control Action, Heat Hysteresis, CZ Proportional Band, CZ Integral Time, CZ Derivative Time, HZ Proportional Band, HZ Integral Time, HZ Derivative Time, Cycle Time, Overshoot Inhibit, Cutoff Factor

Password

Exit

Change Password

Exit Setup Mode

Accessing Group & Parameters

The Figure 4.1 below illustrates how to access the group and parameters. The example shows changing the value for the parameter ‘Setpoint High Limit’ from 600.0 to 100.0 that is located under group ‘Control’.

Figure 4.1

TEMP HIGH

25.0

ENTER PASSWORD >>

°C

25.0

ENTER PASSWORD >>

123

RUN Mode

Main Screen

SELECT GROUP>>

SERIAL

First Group

SETPOINT HI LIMIT >>

600.0

Desired Parameter

for Operator Parameters

Press SET-UP Key for Password Entry

SELECT GROUP>>

Press UP/DOWN Keys

to Select Desired Group

SETPOINT HI LIMIT >>

Press UP/DOWN Keys

to adjust Parameter Value

Default Password

CONTROL

Desired Group

100.0

Desired Parameter

Value

Supervisory Parameters

Press UP/DOWN Keys

To adjust Password Value

Press ENTER Key

to Access Parameters

Press ENTER Key to

store the Value

and move to Next

Parameter

Password for

TUNE >>

First Parameter in

selected Group

HEAT CTRL ACTION >>

PID

Next Parameter

Press & Release

ENTER Key for the

First (Desired) Group

Press UP/DOWN Keys

to Select Desired Parameter

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Notes

The Last Parameter in the selected Group rolls back to the ‘SELECT GROUP’ screen again to avoid re-entering the password in case parameters under multiple groups need to be set.

Parameter Descriptions

The various Supervisory Parameters have been described with their respective group & sub-group.

SUPERVISORY SENSOR INPUT

Parameter Description

ZERO OFFSET >>

This value is algebraically added to the measured Temperature Value at control channel to derive the final value that is displayed and compared for alarm / control. Use this value to nullify any known constant error.

Final Value = Measured Value + Offset

SUPERVISORY SERIAL PARAMETERS

Parameter Description

DEVICE ID >>

Unique numeric code assigned to the for identification by indicator the host. Set the value as required by the host.

Settings

(Default Value)

-50.0 to 50.0

(Default : 0.0)

Settings

(Default Value)

1 to 127

(Default : 1)

BAUD RATE >>

Communication speed in ‘Bits per Second’. Set the value to match with the host baud rate.

PARITY >>

One of the communication error trapping features. Select the data packet parity as implemented by the host protocol.

SERIAL WRITE PERMISSION >>

Setting to ‘No’ disallows the host to set / modify any parameter value. The host, however, can read the value.

2400 4800

9600 19200 38400 57600

(Default : )9600

None Even

Odd

(Default : Even)

Yes

(Default : No)

Zenex Plus User Manual

SUPERVISORY CONTROL

Parameter Description

TUNE >>

(Available for Heat Only / Heat+Cool Control Strategy)

Set ‘Yes’ to activate and ‘No’ to abort the Tuning operation.

SETPOINT LO LIMIT >>

This parameter sets the minimum limit on the Control Setpoint value.

SETPOINT HI LIMIT >>

This parameter sets the maximum limit on the Control Setpoint value.

COMPRESSOR SETPOINT >>

(Available for ‘Heat + Cool’ Control Compressor PV with based Strategy)

This Setpoint Value is compared with the process value to switch the compressor On/Off with the set compressor hysteresis.

Settings

(Default Value)

Yes

(Default : No)

For Thermocouple Input :

-200 to Setpoint HI Limit For RTD Input :

-99.9 to Setpoint HI Limit (Default : 0.0)

For Thermocouple Input : Setpoint LO Limit to 9999

For RTD Input :

Setpoint LO Limit to 600.0

(Default : 600.0)

0.0 to 100.0

(Default : 45.0)

COMPRESSOR HYST >>

(Available for ‘Cool Only’ ‘Heat + Cool’ Control & with Compressor PV based Strategy)

Differential (dead) band between the compressor ON and OFF states.

HEAT CTRL ACTION >>

(Available for ‘Heat Only’ & ‘Heat+Cool’ Control Strategy)

On-Off

The control algorithm tends to maintain the PV at SP by either switching the output (say, Heater) fully OFF or fully ON. The On and Off switching is differentiated by the user settable ‘Hysteresis Band’.

PID

The control algorithm uses a 2nd order equation to compute the ‘% Output Power’ required to maintain the PV at SP. The constants P, I, D are automatically set by the controller.

HEAT HYST >>

(Available for ‘ON-OFF’ Heat Control Action)

Sets a differential (dead) band between the ON and OFF states. Keep it large enough to avoid frequent switching of the load without losing the desired control accuracy.

0.1 to 99.9

(Default : 2.0)

ON-OFF

PID

(Default : PID)

0.1 to 99.9

(Default : 0.2)

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Heat Only Control

PROPORTIONAL BAND >>

0.1 to 999.9

(Default : 50.0)

INTEGRAL TIME >>

0 to 3600 sec

(Default : 100 sec)

DERIVATIVE TIME >>

0 to 600 sec

(Default : 16 sec)

CYCLE TIME >>

0.5 to 100.0 sec

(Default : 10.0 sec)

Heat + Cool

Control Zone : Single

PROPORTIONAL BAND >>

0.1 to 999.9

(Default : 50.0)

INTEGRAL TIME >>

0 to 3600 sec

(Default : 100 sec)

DERIVATIVE TIME >>

0 to 600 sec

(Default : 16 sec)

CYCLE TIME >>

0.5 to 100.0 sec

(Default : 10.0 sec)

Heat + Cool

Control Zone : Dual

CZ PROP BAND >>

Proportional Band for

Cool Pre-dominant zone

0.1 to 999.9

(Default : 50.0)

CZ INTEGRAL TIME >>

Integral Time for

Cool Pre-dominant zone

0 to 3600 sec

(Default : 100 sec)

CZ DERIVATIVE TIME >>

Derivative Time for

Cool Pre-dominant zone

0 to 600 sec

(Default : 16 sec)

HZ PROP BAND >>

Proportional Band for

Heat Pre-dominant zone

0.1 to 999.9

(Default : 50.0)

OVERSHOOT INHIBIT >>

Enable

Disable

(Default : Disable)

CUTOFF FACTOR >>

1.0 to 2.0 sec

(Default : 1.2 sec)

OVERSHOOT INHIBIT >>

Enable

Disable

(Default : Disable)

CUTOFF FACTOR >>

1.0 to 2.0 sec

(Default : 1.2 sec)

HZ INTEGRAL TIME >>

Integral Time for

Heat Pre-dominant zone

0 to 3600 sec

(Default : 100 sec)

HZ DERIVATIVE TIME >>

Derivative Time for

Heat Pre-dominant zone

0 to 600 sec

(Default : 16 sec)

CYCLE TIME >>

0.5 to 100.0 sec

(Default : 10.0 sec)

OVERSHOOT INHIBIT >>

Enable

Disable

(Default : Disable)

CUTOFF FACTOR >>

1.0 to 2.0 sec

(Default : 1.2 sec)

Zenex Plus User Manual

PROPORTIONAL BAND

Sets proportional gain (% power per unit error). Defined in same units and resolution as that for PV.

INTEGRAL TIME

Sets integral time constant in Seconds. Setting the value to 0, cuts-off the integral action.

DERIVATIVE TIME

Sets derivative time constant in seconds. Setting the value to 0, cuts-off the derivative action.

CYCLE TIME

Sets the total ‘On + Off’ time in seconds for time proportional power output through Relay / SSR for OP1.

OVERSHOOT INHIBIT Set this parameter to ‘Enable’ if the process exhibits unacceptable overshoot upon start-up or a step change in SP. If enabled, the controller controls the rate of change of PV to minimize overshoot while approaching the target SP.

CUTOFF FACTOR

This parameter adjusts the effectiveness of the Overshoot Inhibit feature. Increase the value if the overshoot is curbed but the PV takes longer to reach the SP. Decreases the value if the overshoot persists.

SUPERVISORY PASSWORD

Parameter Description

CHANGE PASSWORD >>

The Controller is shipped from the factory with a default password ( ) for accessing the parameters reserved for the 123 equipment manufacturer. owever, if required the password can be changed H by setting the new value for this parameter.

(The new password replaces the old password. hat is, the old T password is no longer valid. it is user’s responsibility to memorize the password.)

SUPERVISORY EXIT

Parameter Description

Settings

(Default Value)

1000 to 1999

(Default : 123)

EXIT SETUP MODE >>

Select to quit Setup mode and return to Main Display mode.

Zenex Plus User Manual

Section 5

FACTORY PARAMETERS

The various parameters have been assembled in various group under the default factory password 321.

Refer Table 5.1 below for a quick summary of parameters under different groups. Each parameter has been described in subsequent sections.

Table 5.1

Group

Sensor Input

Alarm

Input Type, Filter Constant

Hysteresis, Inhibit

Parameters

Control Strategy, Compressor Strategy, Boundary Set Value,

Heat Cool Select

Control Zones, Time Delay (Sec)

Enable, Start Band, Holdback Strategy, Hold Band,

Timer

Door Open

Factory Default

Password

Exit

Heat Off, Cool Off, Power Recovery

Enable/Disable, Switch Logic, Door Alarm Delay

Set to Default Yes/No

Change Password

Exit Setup Mode

Accessing Group & Parameters

The Figure 5.1 below illustrates how to access the group and parameters. The example shows changing the value for the parameter ‘Hysteresis’ that is located under group ‘Alarm’ from 0.2°C to 0.5°C.

Figure 5.1

SELECT GROUP>>

CTRL SENSOR INPUT

TEMP HIGH

25.0

°C

25.0

ENTER PASSWORD >>

321

RUN Mode

Main Screen

SELECT GROUP>>

ALARM

Desired Group

for Operator Parameters

Press SET-UP Key for Password Entry

Press ENTER Key

to Access

Desired Parameters

Default Password

Press UP/DOWN Keys

HYSTERESIS >>

0.2

First Parameter in

selected group

To adjust Password

Value

Press UP/DOWN

Keys to Adjust

parameter Value

Desired Password

ENTER Key for the

HYSTERESIS >>

0.5

Desired Parameter

Value

Press ENTER Key

to Store the New Value

& Move to Next Parameters

Press & Release

First Group

Press UP/DOWN

Keys to Select Desired Group

INHIBIT >>

YES

Next Parameter in

selected group

Notes

The Last Parameter in the selected Group rolls back to the ‘SELECT GROUP’ screen again to avoid re-entering the password in case parameters under multiple groups need to be set.

Zenex Plus User Manual

Parameter Descriptions

The various Factory Parameters have been described with their respective group & sub-group.

FACTORY CONTROL SENSOR INPUT

Parameter Description

INPUT TYPE >>

Select Input type in accordance with the type of Temperature sensor (Thermocouple / RTD) connected for measurement.

FILTER CONSTANT >>

Sets the time constant, in Seconds, for the low-pass digital filter applied to the measured PV. The filter helps smoothing / averaging the signal input and removing the undesired noise. The higher the filter value the lower the indication response to the PV changes and vice-a-versa.

Table 5.2

Option

Type J (Fe-K)

Type K (Cr-Al)

Range (Min. to Max.)

0 to +960°C

-200 to +1376°C

Settings

(Default Value)

Refer Table 5.2

(Default : RTD Pt100)

0.5 to 60.0

(Default : 0.5)

Resolution & Unit

Type T (Cu-Con)

Type R (Rh-13%)

Type S (Rh-10%)

Type B

Type N

Reserved for customer specific Thermocouple type not listed above. The type shall be specified in accordance with the ordered (optional on request) Thermocouple type.

RTD Pt100

-200 to +387°C

0 to +1771°C

0 to +1768°C

0 to +1826°C

0 to +1314°C

-99.9 to +600.0°C

1 °C

0.1 °C

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FACTORY ALARM PARAMETERS

Parameter Description

HYSTERESIS >>

This parameter sets a differential (dead) band between the ON and OFF Alarm status change. Keep it large enough to avoid frequent switching of the Alarm Status/Relay.

INHIBIT >>

Yes

The Alarm activation is suppressed until the Temperature value is within Alarm limits from the time the controller is switched ON. This allows suppressing the Alarm during the start-up Alarm conditions.

The Alarm is not suppressed during the start-up Alarm conditions.

Settings

(Default Value)

0.1 to 99.9

(Default : 0.2)

YES

(Default : YES)

FACTORY

The PPI “Multi-Purpuse Temperature Controller” provides control outputs for driving, both, heating & cooling sources. The user can enable any one or both outputs depending upon the test equipment type and application. If both outputs are enabled (by setting the parameter ‘Control Strategy’ to Heat + Cool) and if the cooling source is compressor then the controller offers various strategies for switching the compressor as described below.

HEAT COOL SELECT

Compressor Switching Strategies

1. Compressor Off

The compressor is kept Off. This strategy is usually selected for temperature values significantly above the ambient

temperature.

2. Compressor On

The compressor is kept On regardless of the measured or set temperature value. This strategy is usually selected for

temperature values significantly below the ambient temperature.

3. SP Based Strategy

In this strategy, the chamber temperature range is split in two zones by setting the parameter 'Boundary Set-point' (BSP).

Refer Figure 5.2.

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Figure 5.2

70°C

Temp. Control SP in

Heat Pre-dominant Zone

50°C

Boundary Set-point

Compressor Status

45°C

30°C

0°C

OFF

Temp. Control SP in

Cool Pre-dominant Zone

The zone at and above the boundary SP ( ) is referred as Heat Pre-dominant zone and that below the boundary SP ) ( is referred as Cool Pre-dominant zone. The controller automatically switches between the two zones depending upon the Temperature SP. If the Temperature SP is below boundary SP, Cool Pre-dominant zone is active and the compressor is kept ON. If the Temperature SP is at or above boundary SP, Heat Pre-dominant zone is active and the compressor is kept OFF. This strategy eliminates the need for the user to manually switch the compressor ON or OFF.

I Control Zones “Dual”; separate tuning can be performed in the Cool and Heat Pre-dominant zones for f the parameter is set to accurate control in each zone. The controller maintains separate sets of Proportional Band, Integral Time & Derivative Time constants for each zone that are automatically selected and used by the controller depending upon the active zone.

However, if the parameter Control Zones is set to “Single”; the controller uses a single set of Proportional Band, Integral Time & Derivative Time constants for both zones.

4. PV Based Strategy

In this strategy, the compressor is switched to cool down the air temperature. The controller switches the compressor ON

or OFF based on the comparison between the et emperature values. Refer Figure below.Measured & S T 5.3

Figure 5.3

Measured Temperature Temperature SP

Compressor Switch-ON Level Compressor Switch-OFF Level

Temperature SP = 20.0°C Compressor Set-point = 1.0°C Compressor Hysteresis = 1.2°C

Compressor Switch-ON Level = 20.0 + 1.0 = 21.0°C Compressor Switch-OFF Level = 21.0 - 1.2 = 19.8°C

21.0

20.0

19.8

°C

Compressor Status

OFF

The compressor is turned ON if the chamber air temperature value is above the Temperature SP by an amount set by the parameter 'Compressor Set-point'. That is;

Compressor Switch - ON Level = (Temperature SP) + (Compressor Set-point)

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Once the air temperature falls below Compressor Switch-ON Level by an amount set by the parameter 'Compressor Hysteresis', the compressor is turned OFF. That is;

Compressor Switch - OFF Level = (Compressor Switch-ON Level) – (Compressor Hysteresis)

The hysteresis inserts a dead band between the Compressor Switch-ON Level and Compressor Switch-OFF Level to avoid frequent switching of the compressor.

Compressor Time Delay

Once the compressor is switched off, a time delay is desired before it is turned ON again. The time delay prevents the possible damage due to short cycling. When the compressor switches off, it spins backward as pressure equalizes. If compressor is energized while it is still spinning backward, it continues to run backward until it trips on internal overloads. This may cause damage to the compressor.

The time delay cycle is executed every time the compressor is turned off. The compressor turning off may be a result of power failure or the on-off control algorithm executed by the controller. The controller in “Auto Mode” monitors the Process Value (PV) against the Set-Point (SP) and attempts to switch the compressor ON or OFF depending upon whether the PV is above or below the SP.

The time delay starts counting down from the instance the compressor is switched off. The compressor is inhibited from switching-on until the delay elapses regardless of the difference between the PV and SP. Once the time delay is elapsed, the control algorithm switches the compressor ON as and when the PV is above SP.

Figure 5.4

°C

PV (Temperature) SP

Compressor Switch-ON Level Compressor Switch-OFF Level

Temperature SP = 20.0°C Compressor Set-point = 1.0°C Compressor Hysteresis = 1.2°C

Compressor Switch-ON Level = 20.0 + 1.0 = 21.0°C Compressor Switch-OFF Level = 21.0 - 1.2 = 19.8°C

Compressor Status

21.0

20.0

19.8

OFF

Case 2 Case 3Case 1

The figure 5.4 above illustrates 3 cases. Case (1) illustrates power-up delay. In case (2); the time elapses before PV rises above the SP. The compressor is thus switched ON as soon as the PV rises above the SP. In case (3); the PV rises above the SP while the time delay is still in progress. The compressor is switched ON as soon as the delay time elapses.

Table 5.2 lists various parameters required for setting-up appropriate compressor switching strategy and associated parameters.

For parameter description the user is requested to read the preceding section.

Zenex Plus User Manual

Table 5.2

Parameter Description

CONTROL STRATEGY >>

Heat Only

Used in applications like Heating Oven, Vacuum Oven, Muffle Furnace, etc.; that require raising the temperature above ambient. The (Heater) control output switches ‘heating source’ for HTR maintaining the temperature at desired setpoint. The CMP (Compressor) control output is inactive (kept off).

Cool Only

Used in applications like Deep Freezer, Cold Cabinet, Lab Refrigerator, etc.; that require lowering the temperature below ambient. The (Compressor) control output switches ‘cooling CMP source’ for maintaining the temperature at desired setpoint. The HTR (Heater) control output is inactive (kept off).

Heat + Cool Used in applications like Environment Chamber, BOD Incubator,

etc.; that require either lowering the temperature below or rasing the temperature above ambient. Both, the (Compressor) CMP and (Heater) control outputs switch ‘cooling source’ & HTR ‘heating source’, respectively, for maintaining the temperature at desired setpoint.

Settings

(Default Value)

Heat Only Cool Only

Heat + Cool

(Default : Heat + Cool)

TIME DELAY (SEC) >>

COMPRESSOR >>STRATEGY

CONT. ON SP BASED PV BASED

TIME DELAY (SEC) >>

0 to 1000 Sec

(Default : 200 Sec)

Control Strategy : Cool Only

Control Strategy : Heat + Cool

BOUNDARY SET VALUE >>

0.0 to 100.0

(Default : 45.0)

CONTROL ZONES >>

SINGLE

DUAL

(Default : SINGLE)

0 to 1000 Sec

(Default : 200 Sec)

CONT. OFF

CONT. ON SP BASED

PV BASED

(Default : SP BASED)

TIME DELAY (SEC) >>

0 to 1000 Sec

(Default : 200 Sec)

TIME DELAY (SEC) >>

0 to 1000 Sec

(Default : 200 Sec)

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FACTORY TIMER PARAMETERS

Parameter Description

ENABLE >>

Yes

Timer function and Start / Abort commands are enabled.

Timer function and Start / Abort commands are disabled.

START BAND >>

After issuance of start command, the timer starts counting down once the PV enters the process band around SP defined by this parameter value.

HOLDBACK STRATEGY >>

None

PV based timer pause is not required.

Up Timer is paused if PV is outside holdband SP.above

Down Timer is paused if PV is outside holdband SP.below

Settings

(Default Value)

Yes

(Default : No)

0 to 999.9

(Default : 0.5)

None

Down

Both

(Default : None)

Both

Timer is paused if PV is outside holdband either above or below SP.

HOLD BAND >>

Sets the temperature limit(s) with respect to the SP for the timer to pause. The timer holds on counting should the PV cross the limit(s).

HEAT OFF >>

Heater is turned off, once Timer operation is over.

COOL OFF >>

Compressor is turned off, once Timer operation is over.

POWER RECOVERY >>

Abort

The timer operation is suspended until a new start command is issued.

Re-Start

The timer re-runs the complete time.

0.1 to 999.9

(Default : 0.5)

Yes

(Default : No)

Yes

(Default : No)

Abort

Restart

Continuous

(Default : Restart)

Continue

The Timer resumes operation for the balance time.

Zenex Plus User Manual

FACTORY DOOR OPEN

Parameter Description

ENABLE >>

Set to ‘Yes’ if is mounted for detecting Switch door Open / Close position.

SWITCH LOGIC >>

Close : Door Open The Door position is considered if the switch is CLOSE.Open

Open : Door Open The Door position is considered if the switch is OPEN.Open

DOOR ALRM DLY (SEC) >>

This parameter sets a timer. From the time the door is opened, the timer begins counting down. If the door is not closed before the timer reaches 0, the Door Open alarm is activated.

FACTORY FACTORY DEFAULT

Settings

(Default Value)

YES

(Default : NO)

CLOSE : DOOR OPEN

OPEN : DOOR OPEN

(Default : CLOSE : DOOR OPEN)

0 to 1000 Sec

(Default : 60 Sec)

Parameter Description

SET TO DEFAULT >>

Set to ‘Yes’ to set all the parameter values to their Default alues.V

FACTORY PASSWORD

Parameter Description

CHANGE PASSWORD >>

The Controller is shipped from the factory with a default password (321) for accessing the parameters reserved for the equipment manufacturer. owever, if required the password can be changed H by setting the new value for this parameter.

(The new password replaces the old password. hat is, the old T password is no longer valid. it is user’s responsibility to memorize the password.)

Settings

(Default Value)

YES

(Default : NO)

Settings

(Default Value)

2000 to 2999

(Default : 321)

Zenex Plus User Manual

FACTORY

EXIT SETUP MODE >>

Select to quit mode and return to mode.Setup Main Display

EXIT

Parameter Description

Zenex Plus User Manual

Section 6

PANEL MOUNTING AND ELECTRICAL CONNECTIONS

WARNING MISH A N D L I N G / NE G L I G E N C E CAN RESULT IN PERSONAL DEATH OR SERIOUS INJURY.

PANEL CUTOUT

Figure 6.1(a) : Old Version

Figure 6.1(b) : New Version

Panel Cutout

75 X 152 mm

-0, +1.0 mm

Panel Cutout

75 X 150 mm

-0, +1.0 mm

PANEL MOUNTING

Follow the steps below for mounting the instrument on panel :

1. Prepare a cutout to the size shown in Figure 6.1.

2. Remove the Panel Mounting Clamp from the instrument Enclosure.

3. Insert the rear of the enclosure through the panel cutout from the front of the mounting panel.

4. Fix the mounting clamp pair such that it ensures secured mounting of the enclosure against the panel wall.

ELECTRICAL CONNECTIONS

1. The user must rigidly observe the Local Electrical Regulations.

2. Do not make any connections to the unused terminals for making a tie-point for other wires (or for any other reasons) as they may have some internal connections. Failing to observe this may result in permanent damage to the controller.

3. Run power supply cables separated from the Sensor cables (Thermocouple / RTD). If the cables are run through conduits, use separate conduits for power supply cable and low-level signal cables.

4. Use appropriate fuses and switches, wherever necessary, for driving the high voltage loads to protect the controller from any possible damage due to high voltage surges of extended duration or short-circuits on loads.

5. Take care not to over-tighten the terminal screws while making connections.

6. Make sure that the controller supply is switched-off while making/removing any connections or removing the controller from its enclosure.

CONNECTION DIAGRAM

The Electrical Connection Diagram is shown on the Top (Old Version) or Back (New Version) side of the controller enclosure. The diagram shows the terminals viewed from the REAR SIDE with the controller Front Label upright. Refer figure 6.2(a) for Old Version & 6.2(b) for New Version.

Zenex Plus User Manual

Figure 6.2(a) :

Old Version

1 2

Pt100

Heater Control

23 3227

25 31302928

EXT.

VOLTAGE

DO-1 DO-2 DO-3

+-+-+

2 3

Control

- -

Compressor

16 17

AI-1 AI-2

DO-4

Process

Alarm

+ +

DO-5

9 106 7 85

Event

Alarm

19 20 21

Figure 6.2(b) :

New Version

AI-1 : Process Sensor

Connections

2625

Zenex Plus B124-V2

DI-1

DI-2

DO-6

DI-3

15 16

Pt100

DI-4

DI-5

DI-6

19 20

8 9 10

Door Open

Timer Start

Alarm ACK

22 23

Digital Output

DO-1 : Heater Control DO-2 : Compressor Control DO-3 : Process Alarm DO-4 : Event Alarm DO-5 : Unused DO-6 : Unused

Digital Input

DI-1 : Door Open DI-2 : Timer Start DI-3 : Alarm ACK DI-4 : Unused DI-5 : Unused DI-6 : Unused

11 12

B+ B-

RS485

Serial

85 ~ 264

26 27

SERIAL COMM

85~265VAC

Supply

VAC

33 34

B+ B-

RS485

L N

B124

Zenex Plus

TEMPERATURE SENSOR INPUT

Connect Thermocouple or 3-wire RTD Pt100 sensor as shown below.

RTD Pt100, 3-wire

Connect single leaded end of RTD bulb to terminal T2 and the double leaded ends to terminals T3 and T4 (interchangeable) as shown in Figure 6.3. Use low resistance copper conductor leads of the same gauge and length. Avoid joints in the cable.

Thermocouple

Connect Thermocouple Positive (+) to terminal T2 and Negative (-) to terminal T3 as shown in Figure 6.3. Use correct type of extension lead wires or compensating cable. Avoid joints in the cable.

Old Version

New Version

SUPPLY

Figure 6.3

Pt100

Zenex Plus User Manual

DIGITAL OUTPUTS

Heater Control Output Compressor Control Output Process Alarm Output Event Alarm Output

All the above Control & Alarm outputs are Voltage pulses (12VDC @ 40mA) for driving external SSR or Relay. The ‘+’ and ‘-’ terminals are for voltage ‘Source’ and ‘Return’ paths, respectively. Refer Figure 6.4 below.

Figure 6.4

Heater

Control

New Version

Old Version

DIGITAL INPUTS

Door Open Timer Start Alarm Acknowledge

Potential-free contact closure input terminals are provided as digital inputs. An ‘Open’ or ‘Close’ switch position is detected as input. Refer Figure 6.5.

PC COMMUNICATION PORT

Compressor

Control

Process

Alarm

DI-1:Door Open DI-2:Timer Start DI-3:Alarm ACK

New Version

Old Version

Event Alarm

2118

Figure 6.5

DI-1

DI-2

DI-3

2522

Figure 6.6

B+

Terminating Resistor

(100 to 150 Ohms)

Twisted Wire Pair

New

Version

B-

Old

33 B+

B-

The controller Communication Port is RS485 and requires a similar port at the host (master) end. If, however, the host port is different (say, RS232 or USB), use appropriate protocol converter (say, RS485-RS232 or USB to RS485) for interface.

For reliable noise free communication, use a pair of twisted wires inside screened cable as shown in Figure . The wire 6.6 should have less than 100 ohms / km nominal DC resistance (Typically 24 AWG or thicker). Connect the terminating resistor (Typically 100 to 150 ohm) at one end to improve noise immunity.

Screened Cable

Serial Comm.

Terminals

Zenex Plus User Manual

POWER SUPPLY

As standard, the is supplied with power connections suited for 8 to 264 VAC line supply. Use well-insulated module 5 copper conductor wire of the size not smaller than 0.5mm² for power supply connections ensuring proper polarity as shown in Figure 6.7. module The is not provided with fuse and power switch. If necessary, mount them separately. Use a time lag fuse rated 1A @ 240 VAC.

Figure 6.7

Line

Neutral

Fuse

2 Pole

Isolating Switch

New

Version

Old

Version

21 L

22 N2627

Power Supply Terminals

Zenex Plus User Manual

Process Precision Instruments

101, Diamond Industrial Estate, Navghar, Vasai Road (E),

Dist. Palghar - 401 210.Maharashtra, India

0250 - 2391722/33/37/42 07498799226, 09321985369

support@ppiindia.net sales@ppiindia.net,

w w w . p p i i n d i a . n e t

Apr 2019

PPI Zenex Plus User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual