Wednesday, July 17, 2013

Allan Bradley Control Net



Alan Bradley Control

Abbreviations:

CAN     control area network .  interface on ECU
COS      change of state
CNBR   control net bridge redundant
NUT     network update time
RES       reset
RIUP     remove (insert) under power
RPI       request package inbound
RJ45     Network style connector
STI       Selectable time interrupt (used to communicate with the core, usually 5ms)

Rack

Modules can be removed when under power

·         Any module can be placed in any slot.
·         Modules are not polled (a request for information is sent from the processor to the modules in turn, the modules respond by returning their current state)
·         Modules put data to the backplane such that all modules on the backplane can read it.

Processor

The part number: 1756-1551A
·         The first part indicates, 1756 indicates the rack style, all modules on the rack have this number.
·         The suffix –1551A indicates the amount of memory installed:- 3.5Mbit

The current firmware version (June 2003) is 8.03

RS232 link

The 9 pin RS232 link can be used to connect the laptop to interrogate the processor.  This is not the preferred method as the link is very slow!  See Ethernet connection

Battery

The battery for backup purposes is non re-chargeable, so it is advisable to change the battery when the power is onto the rack.

941948-01 rev B
0022 PROMARK

Key modes

Run:
Processor running; the inputs are read in, the logic operations completed and the outputs set, i.e. scanning.

Rem (remote):
Possible to change from run to prog from a remote, or outside position, usually the control room via the laptop.

Prog (program)
Sets the outputs to a pre-defined, safe state.  This usually leads to an uncontrolled shut down i.e. no VGV movement to control stall and no starting of the AC lube oil pump.

Test
Inputs are read and the logic is scanned but the outputs are not set.

Processor Indicator lamps

·         Run lamp on: Normal running condition
·         I/O lamp constant green: I/O card transmitting data
·         I/O lamp flashing green: At least one I/O card is not responding.  For example the Flex I/O card failure, coaxial cable failure.
·         I/O lamp off: Usually no project loaded.
·         I/O lamp flashing red: Chassis failure; usually requires replacement of chassis.
·         Force lamp on steady yellow: At least one input or output is electrically forced to a required valve.  Often used to test systems.
·         Force lamp flashing yellow: Force values set up but not enabled.
·         RS232 lamp flashing: Indicates communication by the RS232 cable.
·         Battery lamp on steady red: Less than 10% of the battery life available.  (note the battery light off may indicate there is no power to the backplate)
·         OK light off: no power
·         OK light flashing red: recoverable fault.  Usually caused by a fault set as a major fault, this leads to an engine shutdown.  Recoverable refers to the ability to locate and rectify the fault then reload the program and normal running will proceed.
If the I/O to a major card (e.g. fire & gas, fuel supply) the following will occur
1.    Stop the scan
2.    Output to the safe state
·         OK light steady red: non-recoverable error, usually requires firmware update or replacement.

The processor deals with all processes except:
·         Govern
·         Temperature monitoring

SAM or OCX module[1]

Specialist processor to deal with the Governing and temperature monitoring.  The SAM module is essentially a PC (266 MHz Pentium) that fits the Alan Bradley rack.
Changes to the governor parameters are only accessible via the SAM module

The SAM module outputs signals to the backplane where they are seen as inputs by the processor, which will then act on the information.

SAM Indicator lamps

OK lamp constant on: SAM module running
OK lamp constant on red: fault e.g. watchdog timed out
INIT lamp constant on: SAM module booting up.
USR lamp constant on: user configurable (not used)

Ensure the jumper is set to 16 bit at the top of the module.

DC input module

Serial number
I = input
16 = 16 bit

·         Closed contact ⇒ light on
·         Usually used for internal signals

DC output module

Controls such as:
·         DC pump
·         Fire & gas
Controller tags for output points are indicated as follows:
Local3:O:Data:0 to: Local3:O:Data:31
Local3:O:Data:0 3 indicates the slot number in the rack, note start from slot 0
Local3:O:Data:0 O indicates output
Local3:O:Data:0 0 indicates bit zero on the data word of 32 bits

Flex I/O

The field I/O is linked to the Flex I/O

Control net (CNBR)

Using a screwdriver, the network address is set using the slotted indicators . The left-hand indicator represents tens, and the right indicator units.  The screen indicates the network address as follows:

A#01 where 01 indicates the network address.

If it is necessary to change the Control net card set the new card as the old card.


The local wiring goes from the transmitters, switches etc. into the Flex I/O module.  The Flex I/O module outputs via a co-axial cable to the backplane which transmits the information to the processor.

1.    The maximum number of nodes is 99
2.    The maximum nodes per segment is 48

Control net Indicator lamps

Steady green: control net good
Flashing green: searching the network
Steady red: network fault

Ethernet card

·         Ethernet cards transfer information at a high rate i.e. 10 Mbit/s
·         The IP address is stored electronically on the Ethernet card

Device Net

Run at 230 kbit/s (far slower than Ethernet at 10 Mbit/s) to talk to the ECU
The designers are attempting to put the device net services onto the Ethernet to eliminate the Device net.

RS Logix 5000

Software programming tool
Current version = 8.02
A higher version on the laptop will upgrade a lower version on the rack.  This can cause problems if one turbine is upgraded this means it will not be standard amongst a customers fleet.

·         Tags, programs and tasks must be created off line

Tags

Control tags are global i.e. All modules have access to them.
Program tags are local to the program they are defined in.
When saving a project, only save with tags if the engine is cold.  If the engine is hot and the tag values are saved it is unknown what will happen if the engine is started with information about a hot

Forcing output

Only the following can be forced, otherwise the force mask box in Controller tags will be greyed out.
·         Aliased output and input values, digital or analogue
·         Output and input values, digital or analogue.  E.g. Local3:O.Data.23

The force mask in column three of the controller tags can be used to force outputs. E.g.
·         To set a force for Local3:O.Data.0 place a 1 in the output mask box.  See Figure 2
·         To enable the forces From the Forces drop down box and press the Enable All Forces box see Figure 5

Tasks

Tasks with the following icon:  indicate the task is continuously running. And interrupts the processor at the indicated time i.e. 5ms in this instance.
·         Each program contains one main task and up to 31 other tasks.
·         Tasks can be assigned priority from 1 to 15 where 1 is high priority. 

RS Linx

Communication software; Sets the communication device to communicate via serial or Ethernet cable.
Current version 2.4
A flat battery will result in a Minor recoverable fault being displayed.

RS Networks

Software to configure networks
Control net = 3.22
Device net = 3.21

SP (software protection)

Software used to view protected files
Current version = 8.02

Data types

BOOL   1 bit     21 0 or 1                                           e.g. SOL25
SINT     8 bit     28 +127,-128                                   e.g. MCV101 swash plat for starter motor 0 to 100 %
INT      16 bit   216 +32767,-32768                          e.g. SD1 speed probe 0 to 20,000 RPM
DINT    32 bit   232 +2.147 ×109,- 2.147 × 109        e.g. kWH output power 0 to 20,000,000 W, 20 MW
REAL    32 bit   floating point values                        e.g. PT6 0 to 7 bar




Forced signals can be enabled or disabled.  Disabled the normal logic flow acts.
[1] Special applications module
Control net bridge redundant media

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