FC 176 - Sequence Station (CBC01, CSC01)

The sequence station function code provides an interface between the control configuration and the sequence command (CSC) faceplate and controls. This function code passes I/O alarm data to the faceplate. It also allows the operator to place the device driver blocks (function code 123) associated with the outputs into automatic or manual mode, and change the state of an output in manual mode. Additionally, it gives the operator a way to send a hold/initialize input and the initial step number (restart step) to the sequence monitor (function code 124) block.

 

 

Outputs:

Blk

Type

Description

N

B

Hold/initialize output

N+1

R

Initial step number

N+2

R

Unused

N+3

B

Alarm acknowledge key indicator

 

Spec

Tune

Default

Type

Range

Description

S1

N

0

I

2046

Block address of input 1 alarm signal:

0 = normal, 1 = alarm

S2

N

0

I

2046

Block address of input 2 alarm signal:

0 = normal, 1 = alarm

S3

N

0

I

2046

Block address of input 3 alarm signal:

0 = normal, 1 = alarm

S4

N

0

I

2046

Block address of input 4 alarm signal:

0 = normal, 1 = alarm

S5

N

0

I

2046

Block address of input 5 alarm signal:

0 = normal, 1 = alarm

S6

N

0

I

2046

Block address of input 6 alarm signal:

0 = normal, 1 = alarm

S7

N

0

I

2046

Block address of input 7 alarm signal:

0 = normal, 1 = alarm

S8

N

0

I

2046

Block address of input 8 alarm signal:

0 = normal, 1 = alarm

S9

N

0

I

2046

Block address of input 9 alarm signal:

0 = normal, 1 = alarm

S10

N

0

I

2046

Block address of input 10 alarm signal:

0 = normal, 1 = alarm

S11

N

0

I

2046

Block address of input 11 alarm signal:

0 = normal, 1 = alarm

S12

N

0

I

2046

Block address of input 12 alarm signal:

0 = normal, 1 = alarm

S13

N

0

I

2046

Block address of input 13 alarm signal:

0 = normal, 1 = alarm

S14

N

0

I

2046

Block address of input 14 alarm signal:

0 = normal, 1 = alarm

S15

N

0

I

2046

Block address of input 15 alarm signal:

0 = normal, 1 = alarm

S16

N

0

I

2046

Block address of input 16 alarm signal:

0 = normal, 1 = alarm

S17

N

0

I

2046

Block address of output 1 device driver block CO status

S18

N

2

I

2046

Block address of output 2 device driver block CO status

S19

N

2

I

2046

Block address of output 3 device driver block CO status

S20

N

2

I

2046

Block address of output 4 device driver block CO status

S21

N

2

I

2046

Block address of output 5 device driver block CO status

S22

N

2

I

2046

Block address of output 6 device driver block CO status

S23

N

2

I

2046

Block address of output 7 device driver block CO status

S24

N

2

I

2046

Block address of output 8 device driver block CO status

S25

N

2

I

2046

Block address of output 9 device driver block CO status

S26

N

2

I

2046

Block address of output 10 device driver block CO status

S27

N

2

I

2046

Block address of output 11 device driver block CO status

S28

N

2

I

2046

Block address of output 12 device driver block CO status

S29

N

2

I

2046

Block address of current step number

S30

N

0

I

0 - 7

Station Address

S31

N

2

I

2046

Block address of run/hold signal (boolean value):

0 = hold state

1 = run state

S32

N

1612

I

0 - 1612

I/O utilization: ((no. of inputs used) ´ 100) + (no. of outputs used)

S33

Y

0

I

00, 01, 10, 11, 20 or 21

Manual override lockout:

X X

X0 = normal

X1 = lockout

0X = faceplate has run priority

1X = configuration has run priority

2X = no run priority

 

S34

N

1

I

0 or 1

Default mode of outputs:

0 = manual

1 = automatic

S35

Y

9.2E18

R

Full

Last step number (done step number)

S36

Y

0.000

R

Full

Reserved

 

 

 

 

176.1   Explanation

 

Figure 176-1 illustrates a sequential logic process control system interfaced with a sequence station block. The first group of inputs shown are to the input alarm states. These inputs are boolean values that indicate when an alarm state for each digital input exists. When the values are a logic 0, the sequence station block provides the sequence command controller's faceplate with the normal operating states of the inputs. If any of the values become a logic 1, this block provides the faceplate with the alarm condition data. This data causes both the faceplates LED indicator for the inputs in alarm and the alarm LED to flash. If selected, an audible alarm activates also. To return the faceplate to its normal operating state, the operator should depress the ALARM ACK pushbutton and correct the alarm condition for the input.

 

 

 

As an additional feature, the alarm input state inputs can indicate the boolean output value of a block instead of the alarm state. If the block input is specified as negative, the corresponding sequence command faceplate indicates the state of the blocks boolean output. For example, if the output of block 50 goes to LED four, then S4 is -50.

 

Device drivers provide the next group of inputs to the sequence station block. This station block uses the control status outputs of the device driver blocks for two different functions. The first function is to decode the current state of the devices being driven by the sequence master block. There can be three values for this input: 0.0 (good), 1.0 (bad), and 2.0 (waiting). If the value is bad (1.0), then the station block provides the controller's faceplate with the alarm data. The faceplate's display is similar to the input alarm conditions, except the output LED indicator flashes with the alarm LED.

 

The second function of this input is to determine the block address of the device driver block. This address is for the routine that permits the operator to place an output into manual or automatic control with the pushbuttons on the controller faceplate.

 

The next input shown is the current step number provided by the sequence master block. The value of this input has two functions. The first function is that this number goes to the faceplate for operator information. The other function is to allow the sequence station block to provide the sequence monitor block with the current step number. By providing the current step number to that block, the operator can hold the sequence at any step and restart the sequence at that same step if desired.

 

The current step number is the sequence station block's initial step number output. This output along with the hold/initialize output allows performing four different operations. The first is the hold function. To hold the sequence at a certain step, the hold/initialize output changes from a zero to a one to inform the sequence monitor block to hold at that step. To restart at that step, the hold/initialize output changes from a one to a zero and the sequence monitor block starts the sequence at the step seen on the initial step number output of the station block. (The controller faceplate should display hold before pressing the 1 pushbutton to start the sequence at the current step.)

 

The run/hold value <S31> of the sequence station can also start or hold the sequence from the configuration. If the sequence is running, the faceplate or the configuration can put it on hold. To do so, change the run/hold input from a one to a zero. If the sequence is on hold and the run/hold input goes from zero to one, the sequence starts running at the current step number value <S29>. This depends on the priority set by the tens digit of the manual override lockout input (S33). If the tens digit of this specification is a zero, the faceplate has priority over the configuration inputs. Thus, if the faceplate puts the sequence on hold, only the faceplate can start it. If the tens digit of the manual override lockout input equals one, the configuration has priority over the faceplate.  Thus, if the configuration puts the sequence on hold, only the configuration can start it. If the tens digit of S33 equals two, there is no priority and either the faceplate or the

configuration can start the sequence.

 

The other three operations performed with the sequence station block outputs are restart, start and E-STOP. These operations perform similarly to a hold except that the initial step number output places a different step number there depending on the desired operation. When a restart is desired, change the step number from the current step number to a one before the hold/initialize output toggles from one to zero.

 

NOTE: The controller faceplate display should read RESTART? before pressing the 1 pushbutton to start the initialization of the sequence.

 

The start operation can start the sequence at any desired step number. START 01 displays by pressing the 0 pushbutton when RESTART? is shown on the display. Pressing the 0 pushbutton again keeps increasing the step number. Pressing the 1 pushbutton at the desired step number (START XX), places the desired step number on the initial step number output and the sequence monitor block starts the sequence at that step number.

 

NOTE: Specification S5 of function code 175 (sequence executive) must contain the number of steps being used.

 

The E-STOP operation is similar to the restart function except that the initial step number output changes to a zero. This causes the sequence monitor block and its associated sequence

master block to go to the default step zero.

 

176.1.1  Specifications

 

S1 - Alarm I1

Specification S1 is the block address of boolean value indicating input one alarm state.

0 = normal, no alarm

1 = input one is in alarm

 

When input one goes into alarm state, the faceplate indicator for input one flashes, the audible alarm sounds, and the faceplate alarm LED flashes. Once the operator presses the ALARM ACK button, the audible alarm silences and the alarm LED stays on solid. The indicator for input one continues to flash until the alarm condition goes away.

 

The faceplate input indicator flashes the color corresponding to the current logic state of the digital input.

If the block specified number is negative, this specification displays the boolean value of the block output on the faceplates input LED.

 

S2 through S16 -

Alarm I2 through

Alarm I16

 

Refer to S1 - Alarm I1 for explanation.

S17 - Alarm O1

Specification S17 is the block address of device driver block control output status associated with output one.

 

This input has two functions. First, it provides an alarm indication for the output by decoding the control status value.

0.0 = good

1.0 = bad

2.0 = waiting

 

If the control status indicates bad, then output one is in an alarm state in the same manner as the inputs are (refer to S1 -Alarm I1).

 

The second function of the station input is to indicate the block address of the device driver block associated with this output. Calculate this by subtracting one from the block address entered. The location of the device driver block is for the routine that allows the operator to place an output in either manual or automatic control.

 

S18 through S28 -

Alarm O2 through

O12

Refer to S17 - Alarm O1 for explanation.

S29 - CURSTEP

Specification S29 is the block address of the current step number. The value of this block displays on the faceplate when selecting the sequence mode screen. An initiated hold of the sequence also uses this number to allow the sequence command controller to restart at the proper step upon a disabled hold.

 

S30 - STATADR

Specification S30 is the value of the hardware sequence station address that the station function block is representing.

 

S31 - RUN/HOLD

This block input has two functions:

 

First, it controls the mode of the sequence monitor block (function code 124) after start-up. If the input is a one at start-up, the CSC function code automatically enters run mode of the sequence monitor block starting at step one. If this input is a zero at start-up, the sequence monitor block goes into hold mode.

 

Second, it controls the run/hold mode after start-up is complete.  If this input goes from one to a zero and the sequence is running, the sequence station puts the sequence in hold mode. If the input goes from a zero to a one and the sequence is in hold mode, the sequence station puts the sequence in run mode depending on the priority set by S33.

 

S32 - UTIL

Specification S32 is the displayed number of inputs and outputs.

 

((no. of inputs used) ´ 100) + (no. of outputs used)

 

This specification turns off faceplate indicators not being used. This reduces operator confusion by eliminating meaningless information from the faceplate display.

 

For example, when using only 12 inputs and nine outputs on a sequence command, the value to enter for S31 is:

(12 x 100) + (9) = 1200 + 9 = 1209

 

Now only inputs one through 12 and outputs one through nine display on the faceplate.

 

S33 - MANLOCK

Specification S33 is the manual override lockout value.

    

S34 - OUTDFLT

Default mode of outputs at time of initialization.

 

0 = manual; all outputs are in manual control mode after initialization is complete

1 = automatic; all outputs are in automatic control mode after initialization is complete

 

S35 - DONE

Step number at which to halt the sequence and display DONE XX where XX is the step number. This executes a single cycle of a sequence. During normal sequencer operation, the sequence station monitors the current step number <S29> and compares it to the step number S35. If the DONE step is reached, the sequence station issues a HOLD signal that puts the sequence monitor block into a hold state. Also, DONE XX displays on the alphanumeric display.

 

 

 

 

176.1.2  Outputs

 

N

Output N is the hold/initialize output. The value of this output informs the sequence monitor block to hold the sequencer at a particular step or to continue to execute the sequence.

0 = sequencer is in run mode

1 = sequencer will be held at the current step

1 to 0 transition = sequencer should begin execution at the specified initial step

 

N+1

Output N+1 is the initial step number. The initial step number specifies the step where the sequencer should begin execution. This can be used by the sequence monitor block along with its hold/initialize value to start or hold the sequence at particular steps.

 

N+2

Unused

 

N+3

Output N+3 is the ALARM ACK key indicator. This output is a logic 0 during normal operation. Pressing and holding the ALARM ACK key causes the output to become a logic 1. Releasing the ALARM ACK key causes the output to return to logic 0.

0 = normal

1 = ALARM ACK pushbutton depressed

 

 

 

176.2  Applications

 

Refer to the example for the device driver, function code 123.  This example is a batch process using the sequence station block. Also, refer to the Sequence Command Controller

product instruction for detailed faceplate operation description.