KROHNE MFC 010 C Converter - Manual (Page 79)

MFC010 Interface Manual 77
8.6 Saving and Restoring Configuration settings
The contents of the holding registers (see section 7.5 on page 49 ) are stored in non-volatile EEPROM
memory such that when power is applied t o t he M FC010 t he pr evious c onfiguration s ettings w ill be
reloaded. When changing the settings of the holding registers the user must command the MFC010 to
save the changes (using Output State Register No 1001, See section 7.2 on page 39 for details), before
they are saved to the non-volatile memory. The altered values must be saved before they will affect the
measurement values.
The Units settings and User defined unit scaling values are the exception to this rule, they will affect the
transmitted v alue as s oon t hey ar e c hanged. T he c hanges m ust still be stored in the non-volatile
EEPROM memory if they are to be restored on the next occasion that the MFC010 is switched on.
When changes have been made to the configuration but not stored in the non-volatile EEPROM memory
the system will indicate this fact by setting the “Parameters Changed” flag, which can be i nterrogated by
using command 7 (see section 6.7 on page 29 ) or accessing Input State register No. 1004 ( see section
7.3 on page 41 ). This flag will be reset once the command to store the settings is acted upon.
The user can elect to discard the settings that have been written to the MFC010 if they have not been
saved to the non-volatile EEPROM memory, in which case the previously stored settings will be reloaded
from the non-volatile EEPROM memory. This is in effect the same as switching the MFC010 off and back
on again. To discard the settings use Output State register No .1010 (see section 7.2 on page 39 for
details).
It is also nec essary t o s ave t he t otalisers ( using O utput S tate R egister N os. 1015 or 1016) , t o ens ure
actual totaliser values are recalled in case of power loss.
8.7 Implementing User Defined Units
In order to provide a degr ee of flexibility for the Modbus interface when using the MFC010, a facility has
been i ncluded t o al low t he oper ator t o s cale t he t ransmitted v alues t o an oper ator def ined uni t i f t he
required units are not included in the list of standard units for each variable ( see Holding Registers 1020
– 1026 ). To use the User Defined units simply set the units register for the required variable to “0” then
write the required scaling factor to the appropriate register from Holding Register No 3083 to 3091. The
scaling factor will rescale the transmitted value from the internal MFC010 units (see below) to the user
defined scale. NB Be careful as this will change the scaling of all related variables that use the same
units.
Internal Units : Mass Total g, grammes
Mass Flow g/s, grammes per second
Density g/cm 3 , grammes per centimetre cubed
Volume Total cm 3 , centimetres cubed
Volume Flow cm 3 /s, centimetres cubed per second
For example, if the user wished to receive the transmitted Volume Total in “cubic yards” then the value
stored in Holding register No 3085 should be 1.30795 x10 -6 ( i.e. 1yd 3 = 764554.9 cm 3 , so 1cm 3 = 1.30795
x10 -6 yd 3 ).