FC 130 - Plant Loop Gateway Executive (NPPG01-02, INPPR01)

Executive block function codes define the variables that affect module operations. The Plant Loop gateway executive function code defines the global execution characteristics of the

gateway communication module. With the gateway communication module, communication links between widely separated Plant Loops can be established.

 

The communication link can be microwave, radio link, modem, or a direct hookup. Up to 32 Plant Loops can be linked using Plant Loop to Plant Loop gateways. The system handles one local Plant Loop and up to 31 remote loops. Gateways can be configured to operate in one of two modes.

 

The first mode is two way control, which allows exception report data and control to occur in both directions (local to remote and remote to local). In this mode, only two gateways can be linked, one local and one remote. The second mode is one way control, which allows one local gateway to collect exception report data from one or more remote gateways. The local loop can perform control in all the remote loops, but the remote loops cannot perform control in the local loop.

 

Outputs:

Blk

Type

Description

1

B

Port 0 communication status:

0 = good

1 = alarm - bad or no alarm (unused)

2

B

Port 1 communication status:

0 = good

1 = alarm - bad or no alarm (unused)

3

I

Exception reports per second

4

I

Average exception reports per second

5

I

Maximum exception reports per second

6

I

Unused

 

 

 

Specifications:

Spec

Tune

Default

Type

Range

Description

S1

N

0

B

Full

Configuration lock:

0 = no

1 = yes

S2

Y

0

I

0 - 31

Address of remote loop for tuning and configuration

S3

Y

1

I

0 - 63

Address of remote PCU for tuning and configuration

S4

Y

0

I

0 - 31

Address of remote module for tuning and configuration

S5

N

0

I

Full

Port 0, command/reply delay after transmitter turned on (msecs)

S6

N

0

I

Full

Port 0, transmitter turn off delay after command/reply sent (msecs)

S7

N

0

I

Full

Port 1, command/reply delay after transmitter turned on (msecs)

S8

N

0

I

Full

Port 1, transmitter turn off delay after command/reply sent (msecs)

S9

N

30

I

Full

Maximum exception report time (0 - 255 secs)

S10

N

60

I

Full

Communication status watchdog timer (secs)

S11

N

0

I

Full

Action on communication equipment failure:

0 = no action

1 = halt

2 = toggle state of equipment select output

3 = switch primary/secondary state

S12

N

0

I

Full

Number of communication retries

S13

N

0

I

Full

Port data communication characteristics port 0 + port 1

S14

N

0

I

Full

Reserved

 

 

130.1   Explanation

 

Figure 130-1 shows the architecture of the Plant Loop to Plant Loop gateway. In one way control there is one local Plant Loop and up to 31 remote loops. The remote loops can be manned or unmanned, but they are still considered remote. This arrangement provides control for remote installations without having operators at the site. For example, the Plant Loop to Plant Loop gateway could be used to monitor and control drilling platforms during a personnel evacuation.

 

There are two types of loop to loop communication available:  one way and two way. One way or two way control is selected by a dipswitch on the communication module. Function code 131, Plant Loop gateway point definition, defines data type and address for the exception report data that is transmitted over the gateway.

 

One way communication allows the local loop to control and tune the remote loops, but the remote loops can only send exception reports to the local loop.

 

Two way communication occurs between the local loop and one remote loop. With two way communication, not only is the information transmitted between the two loops, but both loops have control capabilities (the local loop can control the remote loop, and the remote loop can control the local loop).

 

 

Each GCM module occupies a PCU address on its loop and always resides at module address two. Each GCM module must have a function code 130 block defined at block one. Specifications

S2 through S4 define the loop address, PCU address, and module address of a remote module for configuration or tuning purposes. These specifications are tunable to allow the operator to change the address of the module being worked in. For all remote GCM modules, S2 always points to the local loop (remote loops cannot communicate directly with each other).

 

A function code 131, Plant Loop gateway point definition, must be defined for each exception reporting point passed through the gateway. Identical Plant Loop gateway point definition function codes must be defined in both the local and remote GCM modules for each point.

 

To tune, monitor, or control a point on a remote loop from the local loop, the operator selects the PCU address that the local GCM module occupies, and any module address other than two.  This initiates monitoring of the module that the GCM module is pointing to as defined by S2, S3 and S4 of the local GCM modules function code 130. All points defined by a function code 131 in both the local and remote GCM modules can be tuned. If the point is a station, remote control memory or remote manual set constant, it can be modified from the local loop.

 

In summary, to tune the local GCM module, select the PCU address of the local GCM module and module number two. To monitor, tune or control a remote module, tune S2, S3 and S4 of the local GCM module to point to the desired remote module. Then, select the PCU address of the local GCM module and any module other than two.

 

NOTE: All GCM modules occupy module address two. They may be any PCU and loop number. However, in two way control, both gateways must have loop address zero. To tune the module selected with the GCM module, select the PCU address of the local GCM module, and select any module address other than two. This will point the operator interface device to the module selected

with S2, S3 and S4 of the local GCM modules function code 130.

 

130.1.1   Specifications

 

S1 - CONFIG

Specification S1 is the configuration lock.

0 = no

1 = yes

If this value is a one, then the operator cannot change the configuration of the GCM module this block defines. That means no function code 131 blocks can be added or deleted.  Once a configuration is locked, it cannot be unlocked. To change a locked configuration, the module must be initialized and reconfigured.

 

S2 - LOOP

Specification S2 is the address of the remote loop containing the  points to be tuned, configured, or monitored.

 

S3 - PCUADR

Specification S3 is the address of the remote PCU containing the points to be tuned, configured, or monitored.

 

S4 - MADR

Specification S4 is the address of the remote module containing the points to be tuned, configured, or monitored.

 

S5 - COMDEL

Specification S5 is the command delay for port zero expressed in milliseconds. This specification defines the amount of time in milliseconds between when a transmitter activates and the actual transmission of the message. It is used when transmission is by radio and there is a lag between when the radio activates and when a message is sent.

 

NOTE: Specification S5 in port zero could be commands or replies depending on communication configuration.

 

S6 - COMSNT

Specification S6 is the command delay for port zero after a command is sent. This specification defines the amount of time in milliseconds between the conclusion of a command and the conclusion of the transmission.

 

NOTE: Specification S6 in port zero could be commands or replies depending on communication configuration.

 

S7 - REPDEL

Specification S7 is the reply delay for port one expressed in milliseconds. This specification is used when the transmission is by radio. It defines the amount of time in milliseconds between when the transmitter is turned on and when transmission of the reply actually begins.

 

NOTE: Specification S7 in port one could be commands or replies depending on communication configuration

 

S8 - REPSNT

Specification S8 is the transmitter turn off delay for port one after reply is sent. This specification defines the amount of time in milliseconds between when a reply is sent and when the transmitter is actually turned off.

 

NOTE: Specification S8 in port one could be commands or replies depending on communication configuration.

 

S9 - MAX

Specification S9 is the maximum exception report time. This defines the maximum interval between updates of information sent on the Plant Loop from station blocks. If the value of a point has not exceeded the significant change defined in the individual modules, a report of its current value will automatically be sent on the Plant Loop at the end of this time period. Exception report time is selected in one second increments, with the default value being one report every 30 seconds.

 

S10 - COMWD

Specification S10 is the communication status watchdog timer. This specification defines an interval that is used to time communications between two gateway modules. Timing starts when a message is sent from the module the function code 130 block resides in. When a return message is received from another gateway module, the timer is reset to zero.

 

S11 - FAULT

Specification S11 defines the action to be taken upon a communications failure. The communications equipment is  considered failed if the gateway cannot communicate within the period specified by S10.

 

0 = no action

1 = halt

2 = toggle state of equipment select output

3 = switch primary/secondary state

 

S12

Specification S12 is the number of communication retries.

 

S13

Specification S13 is the data communication characteristics.  This defines the communication and validation modes of ports zero and one. The ports can be configured for one or two stop bits (even, odd, or no parity) and checksum or CRC-16 validation as shown in Table 130-1. The tens digit of the value is for port one and the ones digit is for port zero.

 

 

S14

Reserved

 

130.1.2  Outputs

 

1

Output one is port zero communication status with quality.  Output block one is available to the Plant Loop as a digital exception report (e.g., function code 45).

 

0 = good

1 = bad

 

There are two communication ports on each GCM module. This block identifies whether the information coming through the first port is valid. Only one port can be in use at a time.

 

2

Output two is port one communication status with quality. Output block one is available to the Plant Loop as a digital exception report (e.g., function code 45).

 

0 = good

1 = bad

 

There are two communication ports on each GCM module.  This block identifies whether the information coming through the second port is valid. Only one port can be in use at a time.

 

3

Output three displays actual exception reports per second.

 

4

Output four displays average exception reports per second.

 

5

Output five displays maximum exception reports per second.

 

6

Unused