100/180 mm PAPERLESS GRAPHIC RECORDER: USER GUIDE
HA028910
Issue 13 Sep 16
User Guide
Page 178
4.3.18 DEMAND WRITES (Cont.)
WRITING TO A SPECIFIC REGISTER (Cont.)
CONFIGURABLE PARAMETERS (Cont.)
Scaling
Whether Scaling appears or not is Model and Parameter dependent. If scaling is re-
quired, the choice may be ‘Decimal Places, or High/Low, again according to Model.
‘ Decimal Places’ allows a dividing factor to be entered. An entry of 1, divides the
returned value by 10. An entry of 2, divides by 100 etc. for successful implementa-
tion, there must be a suffi cient number of decimal places defi ned in the ‘Max Deci-
mal Digits’ confi guration fi eld for the value to be displayed with the required preci-
sion.. ‘None’ leaves the returned value unchanged. ‘None’ leaves the returned value
unchanged.
For some slaves, scale zero (scale low) is returned as value 0 and full scale (scale high)
as value 65,535 (Hex FFFF) with intermediate values having proportionate values.
For example the value 15, would be represented as 32,767 (7FFF) for a channel scale
0 to 30, as would a value of 50 for a channel scaled 0 to 100, and a value of 45 for a
channel scaled 30 to 60. In order to convert this reading to an understandable value,
a scaling factor must be entered. If the low and high scale entries match the slave
channel’s scale, the master reading will be the same as the slave’s reading.
Selecting ‘ High/Low’ allows Scale low and Scale high values to be entered for the
selected parameter. If ‘ None’ is selected, the process value is displayed as a propor-
tion of 65,535.
DEMAND WRITES WITH AUDIT TRAIL
Normal Audit Trail messages include both the new value and the previous value, for example
09/08/08 11:27:58 1) Temp1 Alarm Number 1 Enable Latched was Off
With Demand Writes, the recorder has no way of determining what the value, of the parameter being
written to, was prior to the Write. For this reason no ‘was’ value is included in the message. A typical
Demand Write audit trail message would be:
09/08/08 11:35:10 Write_1 wrote 255.75
Please see
section 4.4.2
for more details of Audit Trail.
