3 writing a parameter, Procedure, Writing a parameter – NORD Drivesystems BU0020 User Manual

Page 94

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PROFIBUS DP

– Supplementary manual options for NORD - Frequency Inverters

94

BU 0020 GB-2612

9.3 Writing a parameter

When transferring parameter orders, it must be taken into account that the slave does not immediately
respond to orders in the parameter channel of the master telegram, but a positive response can be
delayed by one or more communication cycles. The master must therefore repeat the required order
until the corresponding slave response is received. PPO type 1 or PPO type 2 must be selected as the
PPO type.

The acceleration time parameter (PNU = 102

dec

/ 66

hex

) of a frequency inverter should be set to the

value 10sec in parameter set 3. Only the PKW channel is evaluated.

As the acceleration time has a frequency-internal resolution of 0.01sec, a parameter value of 10 / 0.01
= 1000 (3E8

hex

) must be transferred for 2 sec.

Procedure:

Specify order label (Change parameter value (array word)= 7)

Select parameter (P 102

dec

+ 1000 = P 1102 = P 44E

hex

)

Select parameter set 3 (IND = 02)

Set parameter word (1000

dec

/ 3E8

hex

)

Check response telegram (positive for array word = 4)

The telegram is composed as follows in hexadecimal notation:

Word

1

2

3

4

Byte

0

1

2

3

4

5

6

7

Designation

PKE

IND

PWE

PWE

Value

74

4E

02

00

00

00

03

E8

When the order has been fully implemented by the inverter, it responds with (hexadecimal):

Word

1

2

3

4

Byte

3

4

5

6

7

8

9

10

Designation

PKE

IND

PWE

PWE

Value

44

4E

02

00

00

00

03

E8

WARNING

The maximum number or write cycles on the EEPROM of the frequency inverters is limited
to 100,000 cycles. Continuous writing to the EEPROM therefore results in the destruction
of the EEPROM.

Writing to the RAM of the frequency inverter should therefore be used for writing
parameter data. The setting for this is made in parameter P560 of the frequency inverter.

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