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Q: We have various
equipment (IEDs (Intelligent Electronic Devices) such as such as relays, transient recorders, meters) that
supports operator commands via a terminal or terminal emulator. These are
generally simple ASCII messages command and response.
We wish to extract data from the replies and present this information on an
OPC server.
Please advise if you have an OPC server product that allows scripting,
wizard, or other methods of manipulating simple ASCII strings in the above
command-response manner without having to code up your own OPC server. We wish
to extract the data such as frequency error and time deviation, time tag with
the time returned in the message and present as "tags" in the OPC
server etc as if received via a protocol. The commands are very simple - for
instance an Arbiter 1093 GPS satellite clock.
Send to the GPS: "B7" (respond in broadcast mode 1/sec ASCII)
response: "mm/dd/yy hh:mm:ssL ss +f.ffff +t.ttt ppp.pp<cr><lf>"
(every second)
where:
ss = status, 1st character 0 = locked, 1 = unlocked, 2nd
character = IEEE P1344 status
+f.ffff = signed frequency error in Hz
+t.ttt = signed time deviation in seconds
ppp.pp = phase angle, 0 to 360 degrees
L = local time, U = UTC
Other commands to the satellite clock are structured in a similar fashion.
We would also like to be able to send a 'command' plus a 'value' as an ASCII
text string to the satellite clock.
The 'value' such as in the set time deviation command ASCII string
s.fsRD
where s = 0 to +/- 2000 seconds
fs = fractional seconds
RD = the set deviation command
We would want the ability to enter the seconds 'value' into the tag prior to
sending the command.
A: Try
the following definition with our ASCII driver.
Data
Write B7\n
Word Mode
Write %6.2fRD\n
Real SetDeviation
Read (\d\d)/(\d\d)/(\d\d) (\d\d):(\d\d):(\d\d)([LU])
([01])(\d) ([-+]\d+\.\d+) ([-+]\d+\.\d+) (\d+\.\d+)\n
Digital Lock $8
Byte Status $9
String TimeStamp[20] $1 $2 $3 $4 $5
$6 $7
Real FreqError $10
Real Deviation $11
Real PhaseAngle $12
Writing any value to Data.Mode will cause the string "B7<lf>"
to be sent to the GPS. All incoming data will be matched against
the pattern defined after "Read". The [length] in the
String definition is the number of bytes including the terminating zero to be allocated for that
string.
The deviation can be changed by writing to Data.SetDeviation.
The "%6.2f" is a C - style string formatting syntax
meaning print the data in floating point format with two decimal
places.
Q: I need help with
the .def file to correctly parse the data stream that is coming from an Avtron
linear foot counter, unsolicited, every .5 seconds in the following format:
Read \x10\x02\xff\x01\x3e123.456\x10\x03
Where:
\x10\x02\ Start of message
\xff Default destination
\x01 Source ID
\x3e Message type 3e
123.456 ASCII format floating point, length 7
\x10\x03 End of message
If message type is not 3e, then discard. I am only interested in capturing the
ASCII floating point field.
A: Try
Data
Read \x10\x02\xff\x01\x3e(%f)\x10\x03
Real Value $1
Q: I have an IQ Plus
scale interface, which emulates a Mettler-Toledo scale, It send the following
string
[STX]*[SP][SP]000179000000[CR]
What is the way to extract the substring of the first 6 digits of 000179000000
(the second 6 digits is tare, which is not used), I want to extract: 000179
I have tried using
Input
Read \x02\x2A(.)\x20(\d+)\x0D
String Motion $1
Real Weight[6] $2
The motion variable is actually a binary, that depending if it is a 1 or a 0
tells us if the scale is in motion, if it is kilos or pounds, etc., e.g.,
[SP] = 00100000 or when in motion "(" = 00101000.
[STX]*[SP][SP]000179000000[CR]
[STX]*([SP]000173000000[CR]
A: Try
Input
Read \x02\x2A(.)\x20(%06u)\d+\x0D
Digital [6]
"Motion=3,Metric=5" $1
Real Weight $2
Input.Motion is the motion bit.
Q: I discovered that
if the IQ Plus scale displays a negative number, the tare is not zeros, but
spaces. Is there a short cut way to define exactly 6
characters, that can be either digits or spaces?
A: Try
Input
Read \x02\x2A(.)\x20(%06d)[0-9\x20]+\x0D
Digital [6]
"Motion=3,Metric=5" $1
Real Weight $2
This will allow Weight to be a signed number.
%06d for signed number, i.e number that may start with a +, -, space or digit
Q: Following is my
working Weigh-Tronix .def
Input
Read \x20G([-+]%06d)\x20([lk][bg])\x0D\x0A
Real Weight $1
String Mode[3] $2
The scale indicator is configured to display in pounds with no decimal points
and in kilos with one decimal point. How do I accomplish this in the .def.
A: Try
Input
Read \x20G([-+0-9.]+)\x20([lk][bg])\x0D\x0A
Real Weight $1
String Mode[3] $2
Q: Our Fairbanks
Scale Digital Indicator Model H90-5200 has the following definition
Input
Read \x20(\d+)\x20([lk][bg])\x20([GTN][RAT])\x0D\x0A
Real Weight $1
String Units[3] $2
String Mode[3] $3
My question is regarding the String Mode, which can be:
GR = Gross
TA = Tare
NT = Net
But it can be lowercase, denoting that the scale is in motion: ([gtn][rat]) Is
there a way to account for this, that is, defining a String Motion[3] (or
equivalent) so our OPC Client can monitor this tag and prevent database updates,
until the scale has been stabilized with no motion. The idea is to try to have
consistency with our OPC client, since other scales have a specific motion bit
we can detect, separate from the Mode tag.
A: Try
Input
Read \x20(\d+)\x20([lk][bg])\x20([gtnGTN][ratRAT])\x0D\x0A
Real Weight $1
String Units[3] $2
String Mode[3] $3
Digital [16] "Motion=5" $3
Input.Motion will be on if the scale is in motion. This make use of the fact
that bit 5 is on for lower case letters. The Digital array size must be greater than or equal to 16
so that the ASCII driver will not interpret the $3 as hexadecimal.
Q: We have two Veeder-Root
Series 7910 Electronic Predetermining Counter with RS-422. The request message
format includes a Checksum, for example:
SOH 01
Address 03 30 33
Code 00 30 30
Checksum 3C 33 43
EXT 03
"The two character hex checksum represents the negative of the sum of all
data including the start character up to the character preceeding the first
checksum character, parity bits are excluded from the checksum calculation.
Here is the example for the response message:
STX 02
Code 00 30 30
123456. 31 32 33 34 35 36 2E
Checksum 3B 33 42
EXT 03
For the request message the calculation is as follows:
01 + 30 + 33 + 30 + 30 = hex addition C4
C4 converted to binary = 11000100
Inversion = 00111011
00111100 Twos compliment checksum result = 3C converted to
Hex
Can IOServer handle checksums. There is no option to disable checksums,
although I do understand that we can disregard them for the response message.
A: The ASCII
driver does have the ability to generate and check checksum and crc. All we need
to do is to add your checksum sum method to our code library. The ASCII
definition will look something like this
Info
Poll \x01%02u\a00%02X\c(5,0,0,0)\x03
Read \x02%02u\a00\(%u)\x2e%02X\c(5,0,0,0)\x03
Word value $1
%02u\a generate the two digit address, the address is defined by the Address
field of the ASCII device.
%02X\c(5,0,0,0) generate the two digit hex negative check sum.
Q: I have a device
that returns the numerical (sheet) count in hex (field of 5,with left padding
zeros). How do I convert this hex number on the fly so IOServer will display to
the OPC Client the decimal equivalent?
A: Use
0x$1 to convert hex string to decimal
0o$1 to convert octal string to decimal
0b$1 to convert binary string to decimal.
$1 is the default to convert a decimal string to decimal
Q: I have been trying
IOServer today with the view to using it to interface between an OPC client and
a plain ASCII device. For each datapoint, I am aiming to be able to send out a
string to my ASCII device something like "D3.UAI1.V " I want to read
datapoints only when polled from OPC client, I want to extract a value from the
reply string which will be something like "REPLY:24.5" I also want my
OPC item name to be that same as the read string. I also need to be able to
write a value to
the device with a string like "D3.US5.V=34.5" I envisage having a
fairly large def file for a typical project, as I need
to use about 500 points. all with fixed but different addresses. Some will be
RO, others R/W. If I understand correctly I would basically have a list of the
address/string in the def file. Please can you assist in any way.
A: I have
attached a configuration (ascsim.io, ascslave.def,
ascmaster.def) that simulate a slave ASCII device
and a master ASCII device over TCP/IP.
This configuration show the following.
1. A slave device that will respond to read and write
requests from the master.
2. A master device that will issue read and write requests to
the slave, only points that are requested by the OPC client will be polled. Use
the group update time to control the polling rate.
3. The read/write attribute are presented correctly.
4. Use array to reduce that size of the .def file. We use
metacharacter '\i' to handle array.
5. Use multiple devices to represent Dx
We assume that you need a line feed at the end of each message.
Q: Can you help me
with my protocol:
The Poll message is
LDD
Where
L : (LOOP) would be ONE of these characters (
$!"%/)
DD : (ADDRESS) a combination of characters from P to Y.
so an example of polling string should look like
!PQ
THE INCOMING STRING LOOKS LIKE THIS
bbDDTTTLLLLL&
Where
bb: (two bytes with 8 binary flags each) Each bit should be
configured as a TAG
DD: Same as ADDRESS Sent (only used to check if answer was
from same transmitter polled)
TTT: three characters for temperature. Temp TAG
LLLLL : LEVEL (last two positions are for decimal places)
Level TAG
&: End of message
A: You
can try the following definition
# Tank Data
Data
Poll !%s\a
Read (..)%2s\a(%3u)(%f)&
# Digital Status
Digital [16]"PE\tEquation Type=0,MO\tStation
Mode,CA\tControl Action,SWM\tSoftware A/M Mode,DO\tDerivative,PVT\tPV
Tracking,EN\tEnable,PVHA\tPV High Alarm,PVLA\tPV Low Alarm,DVPA\tDeviation Low
Alarm,DVNA\tDeviation High Alarm,EWD\tError Within Dead Band,OLH\tOutput Limit
High,OLL\tOutput Limit Low,SPOR\tSP Out of Range,INI\tPID Initialised" $1
# Temperature
Word Temp $2
# Tank Level
Real Level $3
Add a device to the port for each device required with
Device Address set to PP to YY.
Note the use of the quoted string after the Digital array
definition to allow the symbolic addressing of each binary flags.
Use \x25 instead of % in the Poll String.
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