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Normally the timestamp as supplied from any OPC Server is passed unchanged to
the device.
If the OPC Client writes a word array of exactly 25 words long or string in the following
format.
V:YYYY:MM:DD-HH:mm:SS.sss:q
V Analog Value
: Separator
YYYY Year
MM Month
DD Day
HH Hour
mm Minute
SS Second
sss ms
q quality (0 is good
quality (c0) and non-zero is uncertain quality(40)) then the specified analog
value and timestamp will be passed to the device.
For example, if the analog value is 1 and it happened at
14:30:25.254 on 16 April, 2002, then the message will be
1:2002:04:16-14:30:25.254 Values that are not specified are set to zero.
To use this feature the source OPC Server must be capable of returning the
analog value and timestamp in a single word array of 25 words or as a string.
Each OPC Server have their own method of accessing arrays e.g in RsLinx RSLinx
OPC Server\[GM3_LCU12]Feeder_SOE.GM3_146.SF6LL1_SOE.Data,L25 in the source of
the OPC Gateway item will return an array of 25 words with the control flag and
timestamp.
The OPC Gateway destination item will be something like
IOServer\DNPSlaveAB_12.1.2.015.state
For debugging, if you turn on IOServer.Log File.Log OPC calls, you will see
something like
Write type(x) length(25) size(2) ExtractTime str(1:2002:02:02-12:13:14.678)
If the conversion is unsuccessfully then it will show
ExtractTime str(1:2002:02:02-12:13:14.6789) year(2002) month(2) day(2) hour(12)
min(13) sec(14) ms(6789)
This conversion fails because ms must be less than 1000
Each word contain a single character.
Word refer a unsigned or signed 16-bits integer. The OPC Gateway uses
IOPCAsyncIO3:WriteVQT to copy the value, quality and timestamp to the
destination tag.
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