Scaling of the Current
The
Current Setpoint, Apparent Current Actual Value and Active Current Actual Value process data
are given in per cent of the inverter rated current [% I
N
] and mapped as signed values to the process
data word (16-bit-integer).
Data type:
Integer16
Resolution:
1digit = 0.1 % I
N
Reference:
Inverter rated current
Range:
-3276.8 % ....0..... +3276.7 %
8000
hex
.....0.....7FFF
hex
Valid for:
Apparent current actual value
Active current actual value
Current setpoint
Current limit
Example: Scaling of the current in the process data channel
This example show the coding the higher-level control uses to exchange
Current process data with
the inverter.
Current
Conversion of the scaling
Transferred process data
45 % I
N
45
= 450
dec
= 01C2
hex
0.1
450
dec
or 01C2
hex
resp.
115.5 % I
N
115.5
= 1155
dec
= 0483
hex
0.1
1155
dec
or 0483
hex
resp.
-67 % I
N
-67
= 670
dec
= FD62
hex
0.1
-670
dec
or FD62
hex
resp.
Scaling of the Ramp
The process ramp for acceleration and deceleration is specified in milliseconds relative to a frequency
rate of change of 50 Hz and mapped unsigned to a process data word (16-bit unsigned). The table
below shows the scaling for the process ramp.
Data type:
Unsigned16
Resolution:
1digit = 1ms
Reference value:
delta f = 50 Hz
Range:
0ms ... 65535ms
0000
hex
.... FFFF
hex
Applies to:
Process ramp up/down
Example: Scaling of the process ramp
The inverter is enabled with an acceleration ramp of 300 ms and disabled again through the stop
function using a deceleration ramp of 1.4 s.
Ramp time
Conversion of the scaling
Transferred process data
300 ms
300 ms
⇒
300
dec
= 012C
hex
300
dec
or 012C
hex
resp.
1.4 s
1.4 s = 1400 ms
⇒
1400
dec
= 0578
hex
1400
dec
or 0578
hex
resp.
3
Inverter Control
with Process Data
MOVITRAC
®
31.. Fieldbus Unit Profile
23
Phone: 800.894.0412 - Fax: 888.723.4773 - Web: www.clrwtr.com - Email: [email protected]
