RESULTADOS Y DISCUSIÓN

This chapter describes the fault indicators and redundant controller set up.

Figure 8-1 Fault and Tracking LED locations

Fault Indicators

All Series 3 Plus Controllers feature a front-panel Fault LED and at

least one normally-energized fault relay (CR1/DO1). In addition, dis- crete output CR2/DO2 can be set up as a second fault relay and CR9/DO9 serves as an Auxiliary PCB fault indicator.

Both the CPU and Auxiliary PCBs include watchdog timers that must be regularly reset by their respective control programs. If either of them does time out, it will de-energize that board’s fault relay and reset its CPU chip, thus causing the control program to restart:

• If that restart succeeds, it will reset the time and clear the relay. The Engineering Panel will beep and display “Reset” on the readout (see page 57).

• If it fails, the fault relay will remain de-energized, which can indi- cate either a software error or a hardware problem that prevents the board’s control program from running.

If the CPU PCB faults, it will stop communicating with the Front Panel, which will in turn light the front-panel Fault LED and turn the other thirteen off. If the Auxiliary PCB faults, it will stop communicat-

COMPRESSOR CONTROLS CORPORATION SCROLL MENU

∆

∇

AUTO MAN Tracking Fault Compressor Controllers Tracking Turbine Controllers

106 Chapter 8: Fault Detection and Redundancy

Fault LED and initiate an emergency shutdown failure, while an Extraction Controller will merely indicate an “Aux. Board” alarm. The other thirteen LEDs will operate normally.

CR1/DO1 can also be given a Relay Assigned Function [MODE:D RA 1], which will not affect the Fault LED but does define the condi- tions under which the Modbus DO1 discrete bit will be set. You may select any function as long as it is configured to de-energize the relay when it occurs, but the state of this relay should then be inter- preted accordingly.

If CR2/DO2 is set up as a second CPU fault relay (see Discrete Out- put Jumpers on page 71), it will de-energize when CR1/DO1 does. Its Relay Assigned Function [MODE:D RA 2] only defines the condi- tions under which the Modbus DO2 State discrete bit is set.

Neither of those Modbus bits, which are strictly software controlled, can indicate a hardware fault. The Auxiliary PC’s fault relay cannot be assigned an additional function and has no Modbus discrete bit. In extreme cases, the controller may go completely dead, in which case all fault relays will obviously de-energize but the Fault LED can not be lit. If power is still being supplied to the controller, check the voltage at the Back Panel or FTA 24 Vdc terminals. If no voltage is present, either the Power Supply or its fuse has probably failed.

Power Supply

Failure

A failure of the internal power supply’s 5 Vdc circuit will de-energize all relays and prevent any LEDs from lighting. Failure of the 15 or 24 Vdc circuits will have no direct effect on the fault indicators, but will always cause all analog inputs to read as zero (volts or milliamps). This will generally trigger any relay assigned the Transmitter Failure (Tran) function.

Beginning with software revisions 1056-001 and 1156-001, Speed and Extraction Controllers can be configured to indicate a “Power Supply” alarm and trigger any Internal Power Supply and General Failure (PSF and Fail) relays if a designated analog input fails. This will occur whenever the power supply fails (even if the designated input signal does not), because the controller will then be unable to read that input.

Figure 8-2 Series 3 Plus dual-redundant fault tolerance

Redundant

Controllers

Series 3 Plus Controllers can be installed in a dual-redundant, paired configuration. The main controller in each pair will normally regulate your process while its “hot” backup monitors it via serial Port 1 so it can instantly take over if the main controller should fail. Such applications are configured by enabling Redundant Tracking

[MODE:D fE 1] in both controllers, giving them the same Controller ID Number [MODE:D COMM 0], and connecting them with a switch- ing device (such as our Redundant Control Selector) that:

• clears the Tracking input of the active controller and includes the valve actuator in its output circuit, and

• asserts the Tracking input of the redundant controller and excludes the valve actuator from its output circuit.

Depending on the application, you may also elect to switch other I/O signals, particularly outputs that affect the behavior of other control- lers or devices within your control system.

This switch is triggered by one or more of the main controller’s dis- crete outputs, wired in series with each set up to be de-energized by one of the chosen Switching Conditions. If any such condition is detected, the corresponding relay will de-energize, causing the switch to select the backup controller.

Any tracking controller will light its Tracking LED (see Figure 8-1). Most will also provide other indications, such as displaying their operating states as “Tracking” or setting a Tracking discrete output.

Controller COMPRESSOR CONTROLS CORPORATION ∆ Manual Auto RT Tracking Fault TranFail Fallback ComErr DEV OUT ALT Antisurge Controller AUX Limit 00.0 4.3 Status TRACK ∇ SO MENU SCROLL DISPLAY SURGE COUNT DISPLAY LIMIT AUTO MAN RESET SAFETY ON COMPRESSOR CONTROLS CORPORATION ∆ Manual Auto RT Tracking Fault TranFail Fallback ComErr DEV OUT ALT Antisurge Controller AUX Limit 00.0 4.3 Status RUN ∇ SO MENU SCROLL DISPLAY SURGE COUNT DISPLAY LIMIT AUTO MAN RESET SAFETY ON PROCESS REDUNDANT CONTROL SELECTOR MAIN BACK-UP Switch to Back-Up Switch to Main GREEN ACTIVE RED TRACK Main ControllerBack-Up Analog Output Fault Discrete Tracking Discrete Analog Output Fault Discrete Tracking Discrete Selected Output

Analog Inputs Analog Inputs

108 Chapter 8: Fault Detection and Redundancy

Figure 8-3 Typical redundant switching relay circuit

Switching

Conditions

Automatic switching is usually triggered by the controller fault relays (CR1 or DO-1, see page 105), which should be set for normally- open operation. If a fault relay is configured to indicate an additional condition, either that condition or a hardware fault would trigger a switchover. If more than one of the available relay functions should initiate a control transfer, the others should be assigned to normally- closed relays in series with the fault relay.

For turbine controllers, the Auxiliary PCB fault relay (DO-9) should be configured for normally-open operation and wired in series with DO-1, so an automatic switch to the backup controller will occur if either of them de-energizes.

Beginning with revision 1056-001 and 1156-001, the Speed and Extraction Controllers offer a General Failure (Fail) relay function specifically intended for redundant switching. It indicates one or more conditions that could stem from internal malfunctions, in which case switching to the backup would allow continued operation.

Switching Logic

Typically, the switching circuitry for redundant Series 3 Plus Control- lers provides Main and Backup buttons for manually activating either controller (provided it is healthy) and relay logic that automatically activates the backup controller if it is healthy and its main counter- part is not. Once the backup has been activated, however, control is never automatically returned to the main controller (that must be done by pressing the Main button while that controller is healthy).

Figure 8-3 shows a hardwired implementation of this switching logic, with the M and B relays de-energized (both controllers faulted):

• If the main controller fails or the Backup button is pressed while the backup controller is healthy, relay S will energize, which in turn energizes and latches switching relay SR.

• If the Main button is pressed while the main controller is healthy, relay R will energize, which de-energizes relays S and SR. The normally-open and normally-closed contacts of relay SR are used to open and close the appropriate controller I/O circuits.

CR1 1 2

Main Controller Backup Controller

B CR1 1 2 M B S M SR S Backup R R M Main

Figure 8-4 Switched I/O signal connections

Output

Connections

One function of the redundant switching device is to connect final control elements to the output signals of the active controller. When 4 to 20 mA current loops are employed, that device must also main- tain the continuity of the tracking controller’s output circuits.

The top panel of Figure 8-4 shows how current-loop outputs from redundant controllers should be connected to their individual loop- back inputs (CH8) and a common control element, using normally- open (NO) and normally-closed (NC) contacts controlled by a single switching relay.

Tracking Input

Connections

The other function of the redundant switching device is to energize the tracking input of the tracking controller. For compressor control- lers, that is always discrete input D1. For turbine controllers, it must be assigned to an input provided by the CPU PCB (DI-1 through DI- 8), but never to an Auxiliary PCB input (DI-9 through DI-16).

The bottom panel of Figure 8-4 shows how the tracking inputs of redundant compressor controllers should be connected to the 24 volt transmitter power outputs of both through normally-open and normally-closed switching relay contacts.

Serial Port Set Up

If Modbus While Tracking [MODE:D LOCK 0] is Off, the main and backup controllers can be given the same Computer ID Number

[MODE:D COMM 0 •]. In this case, only the active unit will respond to Modbus data requests and the tracking unit can not be remotely monitored or reconfigured. Redundant controllers with Modbus While Tracking enabled require unique Computer ID Numbers,

D DISCRETE IN D1 24VDC – + D DISCRETE IN D1

Main Controller Backup Controller

24VDC – + + – OUT 1 + CH 8 + – OUT 1 + CH 8 + – Tracking Discretes

Current-Loop Output and Loopback

1N4004 1N4004 FY SR SR SR SR SR SR SR SR

110 Chapter 8: Fault Detection and Redundancy

Figure 8-5 Typical Redundant Control Selector connections

Both controllers in each redundant pair must be connected to the same inter-controller serial communication networks. The backup controller does not transmit over Port 1, but does track the transmis- sions of its active counterpart.

Similarly, only the active controller responds to Port 2 information requests. Because that port’s address is set by the Computer ID Number, Modbus While Tracking is usually disabled in load-sharing applications so both controllers can have the same Port 2 ID.

Redundant

Control Selector

Our Redundant Control Selector (RCS) provides sixteen pairs of NO/NC relay contacts, compatible fault relay inputs, onboard and remote manual selection buttons, and the recommended Switching Logic for connecting a redundant pair of Series 3 Controllers. Figure 8-5 shows a typical application of that device, which is described in detail by data sheet DS300/R.

RCS Power Test The RCS is designed to select one of two redundant 24 Vdc power supplies. Beginning with revision 1056-001 and 1156-001, each Speed or Extraction Controller in a redundant pair can be configured to test and alarm the failure of one of those power supplies.

Simply connect any discrete input assigned the -RS24 function in parallel with the RCS power supply. The controller will then energize any +RS24 relays and signal an “RS 24V Fail” alarm if that input is cleared. The failure of either power supply would trigger this alarm in one controller, thus indicating the switch was operating without redundant power. The failure of both would trigger this alarm in both controllers, thus indicating the selector was not operating.

D OUT 1 DISCRETE IN D1 + CH 8 CR1 1 2 + – TB6

Main Controller RCS Switching Unit Backup Controller

24VDC – D OUT 1 DISCRETE IN D1 + CH 8 CR1 1 2 + – TB6 24VDC – + To Transducer + –

IM300/H Series 3 Plus Hardware Referencemanual

Appendix A Configu ation Parameters

This appendix describes each configuration or tuning parameter dis- cussed in the body of this manual, including:

• its functional name and a description of that function, • the range of values it can be given,

• the sequence of keys you must press to view or change it from the Engineering Panel (often used as an alternate name),

• its confirming display prompt,

• any restrictions on the order in which it must be entered, and • cross-references to the sections of this manual in which the

parameter is discussed.

Keyboard Entry As discussed in Chapter 3, pressing the indicated keys will produce the listed confirming display, which consists of a prompt followed by the current value. For array parameters, that prompt will include a “#” representing the digit corresponding to the array element.

Values that are selected from a list by pressing the decimal key are shown as “Value” or “Valu”. OFF/ON or OFF/HIGH/LOW choices are shown as such and are selected by pressing the corresponding key (0, 1, HIGH, or LOW). Values that are entered by pressing one or more numeric keys are shown as a series of “#” symbols repre- senting digits, possibly including an automatically-placed decimal point. The space before a negative value is replaced by a “–”. A hexadecimal ten leading digit is entered by pressing HIGH and dis- plays as “A” (100.0 is entered as HIGH 0 0 and displays as A0.0).

COND:A f(X) 2 #

and X 2 #

These parameters characterize an Antisurge Controller’s reported flow measurement in multisection compressor applications.

Range: 0.00 to 9.99 percent [X] 0.00 to 9.99 percent [f(X)] Display: X2# #.## [X]

Y2# #.## [f(X)]

Reference: Numeric Parameters. . . 54

COND:D BIAS 1

For controllers equipped with an Auxiliary PCB, this parameter sets the bias used to scale and calibrate the high-current output signal.

Range: .0000 to .9999 Display: B1 .####

Reference: Output Circuit Calibration. . . 99

COND:D BIAS 1. . . 118

Reported Flow Characterizer

Output Scaling Bias

112 Appendix A: Configuration Parameters

COND:D BIAS 2

For controllers equipped with an Auxiliary PCB, this parameter sets the bias used to scale and calibrate the high-current output’s loop- back input signal.

Range: –.9999 to .9999 Display: B2 .####

Reference: Loopback Circuit Calibration . . . 101

COND:D BIAS 2. . . 118

COND:D DISPLAY

0 # –

Each of these parameters defines the label shown when the corre-sponding measured variable is viewed in the Auxiliary Display.

Range: any eight symbols from scrolling list Display: AAAAAAAA (selected symbol flashes)

Reference: List Parameters . . . 51

COND:D DISPLAY

0 # •

Each of these parameters defines the position of the decimal point in the corresponding measured variable display.

Range: 0 #### (no decimal)

1 ###. (trailing decimal)

2 ##.#

3 #.##

4 .### (leading decimal)

Display: 0#. 4321 (selected digit is replaced by •) Reference: Enabling Parameters. . . 49

COND:D GAIN 1

For controllers equipped with an Auxiliary PCB, this parameter sets the gain used to scale and calibrate the high-current output signal.

Range: .0000 to .9999 Display: G1 .####

Reference: Output Circuit Calibration. . . 99

COND:D GAIN 1 . . . 119

COND:D GAIN 2

For controllers equipped with an Auxiliary PCB, this parameter sets the gain used to scale and calibrate the high-current output’s loop- back input signal.

Range: 00.00 to 99.99 Display: G2 ##.##

Reference: Loopback Circuit Calibration . . . 101

COND:D GAIN 2 . . . 119

Loopback Scaling Bias

Measured Variable Label

Measured Variable Decimal

Output Scaling Gain

Note:

GAIN 1 and 2 can only be changed via the Engineering Panel. Loopback Scaling Gain

COND:D OUT 1 –

For controllers that support valve positioning via the high-current output, this parameter determines whether that output is generated as a unipolar or bipolar electrical signal.

Range: Off unipolar output

On bipolar output Display: OT1- OFF/ON

Reference: High-Current Analog Output. . . 92

MODE:D ANIN

LOW

For a Dual-Loop A/P Controller, this parameter defines the minimum value for any offset-zero input’s analog-to-digital variable, below

which that input is considered to have failed. Range: 00.0 to 99.9 percent

Display: ANL ##.#

Reference: Numeric Parameters. . . 53

MODE:D ANIN –. . . 120

MODE:D ANIN #

Each of these parameters identifies the zero level of the corre- sponding analog input signal (relative to its hardware configuration).

Range: Off actual zero (for example, 0 to 5 Vdc) On 20 percent offset zero (e.g., 4 to 20 mA) Display: A# OFF/ON

Reference: MODE TEST 4 . . . 127

MODE:D ANIN #

HIGH

Each of these parameters defines the maximum value for the corre-sponding analog input’s analog-to-digital variable, above which that

input is considered to have failed. Range: 00.0 to 102.4 percent Display: A#H ##.#

Reference: MODE:D ANIN –. . . 120

MODE:D ANIN #

LOW

Each of these parameters defines the minimum value for the corre- sponding analog input’s analog-to-digital variable, below which that input is considered to have failed.

Range: 00.0 to 102.4 percent Display: A#L ##.#

Reference: MODE:D ANIN –. . . 120

Bipolar Output

Transmitter Failure Limit

Offset Zero Input

Analog Input High Alarm Limit

Analog Input Low Alarm Limit

114 Appendix A: Configuration Parameters

MODE:D COMM 0

This parameter identifies the controller in the network connected to its serial Port 1. With the exception of redundant controllers, this ID must be unique within that network.

Range: 1 to 8

Display: Ctrl# #

Reference: Configuring Communications. . . 60

Redundant Controllers. . . 107

MODE COMM 0. . . 121

MODE:D COMM 0 •

This parameter identifies the controller in the networks connected to its serial Ports 2, 3, and 4. With the possible exception of redundant controllers, this ID must be unique within each of those networks.

Range: 01 to 64

Display: Comp# ##

Reference: Configuring Communications. . . 60

Serial Port Set Up . . . 109

MODE COMM 0 •. . . 121

MODE:D COMM 2

This parameter defines the data transmission rate for the Port 2 serial communication channel.

Range: 2400, 4800, 9600

Display: PT2 Valu (press • to select, then ENTER) Reference: List Parameters . . . 50

Configuring Communications. . . 60

MODE:D COMM 3

These parameters define the data transmission rate and parity set- ting for the Port 3 serial communication channel.

Range: 4800, 9600, 19k2 (19200) Even, Odd, None

Display: PT3 Valu (press • to select, then ENTER) PT3 Valu (press • to select, then ENTER) Reference: Configuring Communications. . . 60

MODE:D COMM 4

These parameters define the data transmission rate and parity set- ting for the Port 4 serial communication channel.

Range: 4800, 9600, 19k2 (19200) Even, Odd, None

Display: PT4 Valu (press • to select, then ENTER) PT4 Valu (press • to select, then ENTER) Reference: Configuring Communications. . . 60

Controller ID Number

Note:

COMM 0 and 0 • can only be changed via the Engineering Panel. Computer ID Number

Port 2 Baud Rate

Port 3 Baud Rate Port 3 Parity

Port 4 Baud Rate Port 4 Parity

MODE:D fD 1

This parameter selects the analog input for the flow signal (∆P_o) used to compute a Performance Controller’s measured total flow.

Range: Off measured total flow not calculated 1 to 8 selects corresponding analog input Display: fD1 OFF/#

Reference: Enabling Parameters . . . 48

MODE:D fE 1

This parameter determines whether the controller will operate in its redundant mode when a Track discrete input is asserted.

Range: Off redundant tracking disabled

On redundant tracking enabled Display: fE1 OFF/ON

Reference: Redundant Controllers . . . 107

MODE:D LOCK 0

If redundant controllers are given the same Computer ID Number

[MODE:D COMM 0 •], this parameter must be disabled so that only one of them will respond to Modbus data requests to that address. If they are given different ID numbers, enabling this parameter allows the Modbus host to monitor both controllers.

Range: Off host cannot monitor tracking controller On host can monitor tracking controller Display: LOC0 OFF/ON

Reference: Serial Port Set Up. . . 109

MODE:D LOCK 1

This parameter and Write Inhibit Only [MODE:D LOCK 2] define the level of access (read/write, read-only, or none) that a host device has to the controller’s Modbus data.

Range: Off access defined by Write Inhibit Only

On no Modbus access

Display: LOC1 OFF/ON

Reference: Configuring Communications. . . 60

MODE:D LOCK 2

If Read and Write Inhibit [MODE:D LOCK 1] is disabled, this param- eter defines the level of access (read/write or read-only) that a host device has to the controller’s Modbus data.

Range: Off read and write access

On read access only

Display: LOC2 OFF/ON

Reference: Configuring Communications. . . 60

Mass Flow Input

Redundant Tracking

Modbus While Tracking

Read and Write Inhibit

116 Appendix A: Configuration Parameters

MODE:D LOCK 7

This parameter determines whether Modbus holding register values transmitted through Port 3 are scaled to their full, maximum range or to a slightly smaller, rounded-off range (minimum to maximum / 1.024), thus providing compatibility with distributed control systems using either scaling convention.

Range: Off the controller uses the maximum range On the controller uses the reduced range Display: LOC7 OFF/ON

Reference: Enabling Parameters. . . 47

MODE:D LOCK 9

If you use the Front Panel MENU and SCROLL keys to change the variable displayed in the AUX readout, this parameter determines whether it will automatically revert to displaying the controller status:

Range: Off selected display remains until changed On status display restored after one minute Display: LOC9 OFF/ON

In document FACULTAD DE DERECHO Y HUMANIDADES (página 24-72)