FC 72 - Analog Slave Definition (NAMM02 - IMAMM03)

The analog slave definition function code with function code 71 defines variables that affect the operation of the NAMM02 and IMAMM03 Analog Master Modules. This function code

defines the I/O module type and I/O module terminations for each of the eight input groups to the NAMM02/IMAMM03 Analog Master Module. Function code 72 resides in fixed

block 76. This function code produces no usable outputs.

 

 

Outputs:

Blk

Type

Description

76

None

No usable outputs

 

 

Specifications:

Spec

Tune

Default

Type

Range

Description

S1

N

0

I

0 - 3

I/O module type, blocks 1 - 8, I/O module 0; I/O module types

allowed:

0 = undefined

1 = thermocouple/mV

2 = RTD

3 = high level

S2

N

0

I

0 - 3

I/O module type, blocks 9 - 16, I/O module 0; I/O module types

allowed:

0 = undefined

1 = thermocouple/mV

2 = RTD

3 = high level

S3

N

0

I

0 - 3

I/O module type, blocks 17 - 24, I/O module 0; I/O module types

allowed:

0 = undefined

1 = thermocouple/mV

2 = RTD

3 = high level

S4

N

0

I

0 - 3

I/O module type, blocks 25 - 32, I/O module 0; I/O module types

allowed:

0 = undefined

1 = thermocouple/mV

2 = RTD

3 = high level

S5

N

0

I

0 - 3

I/O module type, blocks 33 - 40, I/O module 0; I/O module types

allowed:

0 = undefined

1 = thermocouple/mV

2 = RTD

3 = high level

S6

N

0

I

0 - 3

I/O module type, blocks 41 - 48, I/O module 0; I/O module types

allowed:

0 = undefined

1 = thermocouple/mV

2 = RTD

3 = high level

S7

N

0

I

0 - 3

I/O module type, blocks 49 - 56, I/O module 0; I/O module types

allowed:

0 = undefined

1 = thermocouple/mV

2 = RTD

3 = high level

S8

N

0

I

0 - 3

I/O module type, blocks 57 - 64, I/O module 0; I/O module types

allowed:

0 = undefined

1 = thermocouple/mV

2 = RTD

3 = high level

S9

N

9

I

0 - 255

TC I/O module address, position 0, TU/RTD pair A

S10

N

9

I

0 - 255

TC I/O module address, position 0, TU/RTD pair A

S11

N

9

I

0 - 255

TC I/O module address, position 0, TU/RTD pair B

S12

N

9

I

0 - 255

TC I/O module address, position 0, TU/RTD pair B

S13

N

9

I

0 - 255

TC I/O module address, position 0, TU/RTD pair C

S14

N

9

I

0 - 255

TC I/O module address, position 0, TU/RTD pair C

S15

N

9

I

0 - 255

TC I/O module address, position 0, TU/RTD pair D

S16

N

9

I

0 - 255

TC I/O module address, position 0, TU/RTD pair D

 

 

72.1  Explanation

 

The NAMM02/IMAMM03 Analog Master Module processes inputs from eight I/O modules through termination devices. The eight I/O modules have addresses from zero to seven with hardware switches on the modules. Each I/O module carries a group of eight inputs. The termination devices connect to the analog master module in a daisy chain arrangement as shown in Figure 72-1. Standard termination device A terminates I/O modules zero and one; standard termination device B terminates I/O modules two and three, etc.

 

In order for the analog master module to read inputs accurately, I/O module type and termination device connections must be specified. Specifications S1 through S8 identify the type of I/O module handling each group of inputs, with I/O module address zero providing inputs to blocks one through eight, I/O module address one supplying blocks nine through 16, etc. Specifications S9 through S16 define the address of I/O module connections to termination units, with S9 identifying the I/O module at position zero on the termination unit daisy chain, S10 identifying the I/O module at position one, etc. Specifications S9 through S16 can be specified for all three types of I/O modules, but they are mandatory for thermocouple I/O modules. They identify the location of the thermocouple termination units so that cold-junction compensation can be made for thermocouple inputs. High level, millivolt, and RTD inputs require no temperature correction.

 

Thermocouples indicate temperature through a voltage developed across a dissimilar metal junction. The voltage then goes to an I/O module through a termination device. Thermocouple wires connected to a termination device create another dissimilar metal junction that produces an additional voltage representing the ambient temperature at the termination device. That voltage subtracts from the thermocouple voltage providing a false value to the analog master module for the thermocouple temperature. Thermocouple termination devices have RTDs to measure the temperature of the junction at the termination device. Those temperature values go to the analog master module with the thermocouple voltage, to correct the temperature. The NAMM02/IMAMM03 internally converts the ambient temperature to a voltage signal and adds it to the thermocouple voltage to provide the correct value. Each standard thermocouple termination device accommodates two I/O modules and has two RTDs for temperature compensation.