100/180 mm PAPERLESS GRAPHIC RECORDER: USER GUIDE
User Guide
Page 165
HA028910
Issue 13 Sep 16
4.3.16 MASTER COMMS (Cont.)
CONFIGURABLE PARAMETERS
This section defi nes those parameters which are unique to user defi ned registers.
Value
Shows the value returned from the selected register, as modifi ed by the scaling fac-
tor (if any).
Function Code
Allows Modbus function code 03 or 04 to be selected. In some implementations,
the functions of the two codes are identical. In others, the codes have different func-
tions. See the documentation supplied with the slave for a list of supported Modbus
codes. For this instrument see
section 8.2.1
.
Register
A decimal number representing the required parameter’s location in the slave’s
Modbus Register map. This information must be determined from the documenta-
tion supplied with the slave. For this instrument, section 8.4 contains listings for a
number of instrument, groups, and input channels. For details of maths, totalisers
etc., refer to the relevant option description.
Data Type
Select a suitable data type for the selected parameter (again from the slave docu-
mentation). For this instrument, a list of relevant data types is given in
section 8.4
.
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 implementation, there must be
a suffi cient number of decimal places defi ned in the ‘Max Decimal Digits’ confi gura-
tion fi eld for the value to be displayed with the required precision. ‘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 proportion of 65,535.
