100/180 mm PAPERLESS GRAPHIC RECORDER: USER GUIDE
HA028910
Issue 13 Sep 16
User Guide
Page 76
BREAK RESPONSE
For thermocouples and other low level inputs (i.e. input voltages less than 150 mV), the recorder can be
made to respond in one of the following ways, if a break in the input circuit is detected.
None trace drifts with the input wiring acting as an aerial.
High trace placed at full scale.
Low
trace placed at scale ‘zero’.
COLD JUNCTION COMPENSATION ( CJC)
For input type = thermocouple, None, Internal, External or Remote can be selected for cold junction
compensation.
INTERNAL
Internal CJC is by means of an RTD connected across pins 11 and 12 of the input board connector.
EXTERNAL
If the cold junction is maintained (by the user) at a known, fi xed
temperature, ‘external’ should be selected. An extra numeric
entry box appears to allow the user to enter the temperature at
which the cold junction is maintained.
REMOTE
‘Remote’ is selected if the cold junction temperature
is to be measured by an external device connected
to the instrument. An extra picklist appears which
allows the user to select any input or maths channel
to act as the cold junction temperature source chan-
nel. The temperature units displayed here, are those
of the channel being confi gured, not those of the CJ source channel. The CJ source channel must be
confi gured appropriately for the external device, and must provide a value which is consistent with the
confi gured channel’s units.
DESCRIPTOR
Allows a text string of up to 30 characters (including spaces) to be entered for the channel descriptor (e.g.
‘Turbine 2 tempA’).
A/B SWITCHING
If enabled, this function allows alternative Span, Zone and Trace Colour values to be entered. ‘A’ values
are used during normal operation. ‘B’ values are switched to by job action, as described in
section 4.7
.
4.3.3 CHANNEL/ALARM CONFIGURATION (Cont.)
FILTER
For ‘noisy’ slowly changing signals, damping can be used to fi lter
noise so that the underlying trend can be seen more clearly. None,
2, 4, 8, 16, 32, 64, 128 or 256 seconds can be selected.
It is not recommended that damping be used on quickly changing
signals.
Input
95%
3 x
Damping
Recorder
response
Effect of damping on step
change in input signal
Break Response
Cold Junction Type
External CJ Temp
Descriptor
None
External
0
Channel 1
Figure 4.3.3c Channel fi lter
Break Response
Cold Junction Type
Remote CJ Temp from
Descriptor
None
Remote
Channel 3 ˚C
Channel 1
