UnOffical PLC 5 Software Manual

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PLC 5 Software Guide and Manual
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UnofficialPLC 5 Software Guide.
Any Station - Generic
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Drawn D J Ray
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Original is A4 Landscape.
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This document forms a guide to SFC programming
that is common to Voith SFC Software.
GCS Support.MERIDIAN ENERGY LTD.State Highway
8,Twizel,New Zealand.
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General Guide
Use a single SBR to connect all discrete digital
inputs to a buffer file.Use a single SBR to
connect all analog inputs to a RAW (un scaled)
buffer file.Use a single SBR to scale all the
analog inputs using CPT instruction use either
inline scaling values or references to a scaling
data file.Make all unit (generator) code the
same across a station use the DH address as a
switch to turn on and off unit specific
functions.Use SFCs where ever possible.Use
standard/generic SFCs where ever possible.Use 1
SBR file for 1 SFC where ever possible.Use 1
Data file for 1 SFC where ever possible however
its likely more than 1 will be needed
often.Describe the inputs to the SFC Digital
and Analog.
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SCADA ALARMING
Every PLC Scan do this the alarm is latched
into N5010 on for reading by scada they are
latched so that a fleeting alarm is held in N50
till scada acknowledges it has read the N50
fileWhen it does ack the alarm value perform a
plain COP to freshen the N50 file
N5010 N4710 OR N5010 (Lgt 40 for N4710 to
N4749)
N47
N50
N50
Logical OR
Indications both bit and integer are not
latched the N50 file is addressed directly in
code.
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PLC 5 Code segement to perform scada Alarm Ack
Value calculation and verification and N50
re-freshing control.
If scada acks the alarms by returning a Alarm
Ack set point hat equals theAlarm Ack Value as
computed by the PLC the scada has seen the
currentN50 file so freshen it.
If scada has not acked the current alarms keep
them and add any new ones.
Initalization
Compute a crude value that can be used to
determine if the alarming file N47 has
changed.Various symetrical bit patten alarm
changes will not be detected.
BST EQU N5151 N5051 BST COP N4710 N5010 40
NXB CLR N5051 BND NXB NEQ N5151 N5051 XIO
R60/EN FAL R60 40 0 ALL N5010 N4710 OR
N5010 NXB XIO R61/EN BST CLR F460 NXB FAL
R61 40 0 ALL F460 F460 N5010 BND NXB NEQ
F460 F461 BST ADD N5051 1 N5051 NXB MOV F460
F461 BND NXB GRT N5051 1000 MOV 1000 N5051 BND
If the alarming file has changed INC the Alarm
Ack Value this is passed to scada.Which will
return it indicating it has seen the current
state of N50
House keeping
Limiting 1,000 is a lot of alarm changes.
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VOITH CAN RTD Alarming Tripping
RTDs Each Fault bit is derived by ths sort of
rung
A trip is derived like this
Or a high alarm like this.
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A SFC Normally 1 per SBR but often more than
one are found in a SBR
A typical Voith SFC consists of the following
code segments in the following order.Inputs
to SFCDerivedStep TimersStep ControlStep
DecoderStep Outpts
Typical overview of the code sctions that make up
a SFCand the order and size they take in any one
ladder file.
Inputs to SFC
Derived
Step Timers
Step Control
Step Decoder
Step Outpts
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This is a standard Voith Step Decoder and
Controller.N80 for step wordsB81 for step
bitsB830 is a buffer location used by many SFC
decoders.N7100 is a buffer location used by
many SFC decoders.Each step is guaranteed to be
true for at lest one scan if the rule below is
used1- Never used the step word for state
tests always use the step bit.