II K 4-39
Overview of Software
4.5.10 Internal Scaling
You can display all parameters of the DCS400 in their
physical quantities by means of operating panel or the
PC tool, in the way they are specified in the column
"Unit" at the parameter list:
A, V, rpm, Hz, %, s, ms, text, integer, mH, mOhm, %/
msec, °C, kW, hex.
In case of serial drive control (reference/actual value
transmission) with PLC (field bus coupling, RS232
port, panel port) the internal scaling of these values
shall be considered. There is no transmission of
physical quantities but values are transmitted in bina-
ry representation.
Example: The maximum speed reference of a drive of
3000 rpm is transmitted in a 16-bit telegram word. In
this case 3000 rpm are equal to the maximum value
of 20.000 decimal i.e. the resolution of the speed is in
steps of 1/20,000. This value 20,000 is transmitted on
the bus as a binary value in a 16-bit combination of "0"
and "1". Each bit has a decimal valency. Hence
20,000 shall be distributed over these 16 bits in such
a way that the decimal sum of set "1's" is again
20,000.
Representation of the decimal value 20,000 as 16-bit
pattern
Line 1 - positions of the 16 bits
Line 2 - decimal valency of each bit
Line 3 - bit combination of "0" and "1", whose check-
sum is 20,000
Other values of the DCS400 are resolved with a
maximum value of 4096.
Table of internal scaling:
This internal scaling does not apply to the transmis-
sion of parameters via PLC. In this kind of transmis-
sion, decimal values are simply transmitted in binary
form i.e. the values of the parameter list are represent-
ed in decimal form and without a decimal point in a 16-
bit word.
Decimal values without decimal point are transmitted
in the same form as they are represented in the
parameter list. In this case, e.g. the parameter Base
Speed (1.05) will be set to 3000 if the nominal speed
is intended to be 3000 rpm.
Decimal values with decimal point are simply trans-
mitted as a number without decimal point but with all
decimal digits. In this case, e.g. the parameter Field
Cur Nom (1.03) will be set to 650 if the nominal field
current is intended to be 6.50 A. Parameters with
other engineering units shall be treated in the same
way.
Exception:
Selection parameters (unit: Text) have a number
preceding the text in the parameter list. Every number
represents a text and/or a function. Overwriting the
number changes the selection in the parameter. If a
such parameter is read the number will be transmit-
ted, not the text.
Incorrect parameter transmission
Writing parameters may cause the output of fault
messages if
• the values are outside of the min. / max.
definition (according to the parameter list)
• writing is on actual value parameters (signals)
or constants
• writing is on parameters which are blocked
during operation
In such cases, a fault telegram will be generated
which must be evaluated in the PLC.
Signal Internal value Corresponds to value
(decimal) (on operating panel or PC tool)
Actual speed value (5.05) 20,000 100% speed in rpm
Speed reference value (5.04) 20,000 100% speed in rpm.
Armature voltage actual value (3.03) 4,096•(U
a
/EMF) 100% nominal armature voltage in V
Armature current reference value (3.01) 4,096 100% nominal armature current in A
Armature current actual value (3.02) 4,096 100% nominal armature current in A
Actual power value (3.21) 4,096 100% power in %
Actual torque value (3.23) 4,096 100% torque in %
Actual field current value (4.02) 4,096 100% nominal field current in A
Actual EMF of motor (3.20) 4,096 100% nominal EMF in V
Default in service procedure Internal value Corresponds to value
Contr Service (7.02) (decimal)
Field current reference 4,096 100% of nominal field current in A
line1 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
line2 32768 16384 8192 4096 2048 1024 512 256 128 64 32 16 8 4 2 1
line3 0 1 00111000100000
To Next Page
Loading...
