181-122018_THCD-101 Instruction Manual
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(c) Input channel full scale – ‘uif’
This command is used to set the full-scale voltage for the input channel. The single parameter is the actual
full-scale value. The full scale voltage setting for the input channel is retrieved using the query ‘uif?’. The data
returned is as follows:
INPUT FULLSCALE: <fs>
… where: <fs> = the full scale voltage of the channel
4.2.6. Filtering commands
(a) Filter band – ‘flb’
This command is used to set the point at which the adaptive filtering kicks in. It takes one parameter which is
the percentage of full scale of the input. Valid values are between 0.01% and 1.00%. Additionally the
parameter can be OFF which will mean the filtering will never kick in, or ON which means the filtering is
always used. Note that if the filter size is set to greater than 5 seconds, the filter band command will return a
Bad Command acknowledgement because the filter is always on in this situation and it therefore makes no
sense to attempt to change the band setting.
To retrieve the current filter band, use the query ‘flb?’. The returned data is:
FILTERING BAND: <band>%
(b) Filter size – ‘fls’
Use this command to set the size of the adaptive filtering buffer. The one parameter this command takes is the
buffer size in seconds, between 0 and 6 seconds. (0 can be used to effectively turn the adaptive filtering off).
To retrieve the current filter size, use the query ‘fls?’. The returned data is:
FILTERING SIZE: <x> sec
… where <x> = number of seconds of filtering
[Note if current size is 0 then returned data is: FILTERING SIZE: 0 (NO FILTER) ]
4.2.7. Relay control commands
(a) Relay trip point – ‘rlt’
This command sets the point at which the relay switches from one state to the other. When the source data is
below this point then the relay is closed, so therefore when the source data rises above this point then the
relay is open. The command takes two parameters – the first is the relay whose trip point is to be set (1-2) and
the second is the trip point in engineering units, as configured with the Input Channel range command (see
6.5(b)). Note that the first parameter is always required even if the second relay has not been factory fitted.
The current trip point values can be retrieved using the query ‘rlt?’. The returned data is one line for each
relay, as follows:
RELAY <x> TRIP POINT: <trip point, in engineering units >
… where ... <x> = the relay number
(b) Relay hysteresis – ‘rlh’
This command configures the hysteresis setting of the relay. It takes two parameters – the first if the relay in
question, the second is the percentage hysteresis, represented as a percentage of full scale of the source
channel, with limits of 0.0% (i.e. no hysteresis) to 10.0%.
The current hysteresis setting can be retrieved using the query ‘rlh?’. The returned data is one line for each
relay, as follows:
RELAY <x> HYSTERESIS: <hysteresis percentage>%
… where ... <x> = the relay number
4.2.8. Other commands
(a) User input rezero – ‘irz’
