FC 47 - Analog Input Exception Report (NAMM01)

Use the NAMM01 analog input exception report function code to configure exception and alarm reports for the NAMM01 Analog Master Module. Refer to function code 70 for NAMM02 exception report configuration. Refer to function code 158 for IMAMM03 enhanced analog point definition.

 

The NAMM01 Analog Master Module has 72 blocks. Each block performs three functions: analog input, exception reporting, and alarm reporting. The number of blocks configured depends upon the number of I/O modules connected to the control module. The NAMM01 has eight internal inputs and 64 additional inputs through analog I/O modules. Each analog I/O module has 16 inputs and the NAMM01 accommodatesfour I/O modules.

 

The outputs section illustrates the fixed block assignments used for NAMM01 inputs. The input value to function code 47 is sent on the communication highway if the maximum report time or significant change is exceeded.

 

Outputs:

Block Numbers

Input Group Address

(8 points per group)

From

To

1

8

NAMM01 internal points

9

16

Group 0 of first I/O module

17

24

Group 1 of first I/O module

25

32

Group 0 of second I/O module

33

40

Group 1 of second I/O module

41

48

Group 0 of third I/O module

49

56

Group 1 of third I/O module

57

64

Group 0 of fourth I/O module

85

72

Group 1 of fourth I/O module

 

 

NOTE:  A code set in S1 identifies the type of analog input. For a one to five volt or four to 20 milliamp linear signal, S1 equals zero, and for a one to five volt or four to 20 milliamp square root extracted signal, S1 equals one.

 

Specifications:

Spec

Tune

Default

Type

Range

Description

S1

N

0

I

0 or 1

Type of signal:

0 = 1-5 VDC or 4-20 mA (linear)

1 = 1-5 VDC or 4-20 mA (square root extracted signal)

S2

N

0

I

0 - 255

Engineering unit identifier

S3

N

0.000

R

Full

Zero of S1 input in engineering units

S4

N

100.000

R

Full

Span of S1 input in engineering units

S5

Y

100.000

R

Full

High alarm point limit value

S6

Y

0.000

R

Full

Low alarm point limit value

S7

N

2.000

R

Full

Significant change (% of span)

 

 

47.1 Explanation

 

Exception Reports

 

An exception report will occur when:

 

Alarm Reports

 

An alarm report generates when the high (S5) or low (S6) limit is reached. The point stays in alarm condition until the input is below (high) or above (low) the alarm limit and deadband (set with S2 of function code 56). For example:

 

The input is zero to 100 percent (S2, S3 and S4). The high alarm (S5) is set to 85 percent and the low alarm limit is set to ten percent. The alarm deadband (function code 52 and 56) is set to 0.5 percent providing a deadband of 0.5 percent.

 

When the input equals ten percent, there is a low alarm. The point stays in alarm until the input is greater than 10.5 percent (low alarm plus deadband). When the input equals 85 percent, there is a high alarm. The point stays in alarm until the input is less than 84.5 percent.

 

Alarm Report Equations

 

1. Y > (S5) and current status not equal high alarm (entering high alarm).

 

or

 

2. Y > [(S6) + DB], and current status = low alarm (exiting low

alarm).

 

or

 

3. Y < [(S5) – DB], and current status = high alarm (exiting high

alarm).

 

or

 

4. Y < (S6) and current status not equal low alarm (entering low alarm).

 

where:

 

Y

=    Current value of the input.

(S5)

=    High alarm point limit value.

(S6)

=    Low alarm point limit value.

DB

=    Alarm DB X (S4)

               100

Alarm DB

=    Alarm deadband, defined by S2 of the executive block, is a buffer zone between the normal and alarm states. It prevents excessive alarm reports when a point value is hovering at an alarm limit. Figure 47-1 shows the use of alarm deadbands.

(S4)

=    Span of S1 in engineering units.

 

 

47.2  Examples

 

Figure 47-1 shows a sample input, with alarm and exception reports identified.