FC 125 - Device Monitor

The device monitor block takes the control status outputs from up to 16 device drivers or device monitors to provide a common control output status. The control output status can be sent to another device monitor block, or to a sequence monitor block that determines the next step in a process. When all inputs are good (0.0), the output is good (0.0). When any input is bad (1.0), the output is bad (1.0). When any input is waiting (2.0) and no input is bad (1.0), the output is waiting.

 

Outputs:

Blk

Type

Description

N

R

Control output status:

0.0 = good

1.0 = bad

2.0 = waiting

 

 

Specifications:

Spec

Tune

Default

Type

Range

Description

S1

N

5

I

Note 1

Block address of CO status 1

S2

N

5

I

Note 1

Block address of CO status 2

S3

N

5

I

Note 1

Block address of CO status 3

S4

N

5

I

Note 1

Block address of CO status 4

S5

N

5

I

Note 1

Block address of CO status 5

S6

N

5

I

Note 1

Block address of CO status 6

S7

N

5

I

Note 1

Block address of CO status 7

S8

N

5

I

Note 1

Block address of CO status 8

S9

N

5

I

Note 1

Block address of CO status 9

S10

N

5

I

Note 1

Block address of CO status 10

S11

N

5

I

Note 1

Block address of CO status 11

S12

N

5

I

Note 1

Block address of CO status 12

S13

N

5

I

Note 1

Block address of CO status 13

S14

N

5

I

Note 1

Block address of CO status 14

S15

N

5

I

Note 1

Block address of CO status 15

S16

N

5

I

Note 1

Block address of CO status 16

 

NOTES:

1. Maximum values are: 9,998 for the BRC-100, IMMFP11/12 and 31,998 for the HAC

 

125.1   Explanation

 

The device monitor block monitors a group of control output status values. It reads those values from a device driver or other device monitor block and outputs a value dependent on the values of the inputs.

 

For example, if a sequence generator block defines output states for ten field devices, the device monitor block associated with that control loop receives the control output status for the devices and generates a common output. That output goes to the sequence monitor block controlling the step output of the sequence generator block. The sequence monitor block then uses that information to select the next step in the process. It is used as a feedback from the field to alert the system of an abnormal state of the field devices.

 

Figure 125-1 illustrates this control scheme. If a control loop controls more than 16 devices, the output of additional device monitor blocks can be fed into another device monitor block to establish a common output. Therefore, no matter how many devices are being controlled by a single sequence generator block, the control output status can be reduced to one value representing all inputs.

 

 

125.1.1Specifications

 

S1 to S16 - COS1 to COS16

Block addresses of the device drivers control status output or the device monitor block containing the control output status values for other monitored devices.

 

 

125.1.2   Output

 

N

Control output status based on the control output status of the devices monitored by the device monitor block.

0.0 = all inputs good

1.0 = any input bad

2.0 = no inputs bad and at least one input waiting

 

NOTE: Only one input must be bad for the output to be bad.

 

125.2   Applications

 

Device monitor blocks can be used to control any system that requires the output of a group of devices be a certain value before a control step is implemented. Refer to function code 123 for an example of the device monitor block used in a batch control process.