Yaskawa V7 PROFIBUS-DP - Manual (Page 47)

Parameter Access B-3
Parameter Access Overview
Parameter access allows the reading and writing of drive parameters. For a detailed description of the V7 drive parameters refer to the V7
MODBUS
®
Technical Manual.
‹ Initialize Data Structures
Prior to setting the command message, insure that the command message handshake byte HS, bit 7, bit matches the HS bit, bit 7, of the
response message.
‹ Set PROFIBUS-DP Master Command Message
„ Function Code: Enter 03h (0000 0011) to read data from the drive or 10h (1010 0000) to write data to the drive. If no
parameter access messaging is required, enter 00h as the function code.
„ Addressing: All register addresses consist of two (2) bytes. The most significant byte, the upper half, is entered as the Starting
Address MSB. The least significant byte, the lower half, is entered as the Starting Address LSB. If more than one V7 register is
to be accessed, only valid with 16 word input/output messages, the registers must be consecutive beginning with the register at
the starting address.
z Starting Address MSB: Enter the upper half of the starting address. For address 1234h, enter 12h.
z Starting Address LSB: Enter the lower half of the starting address. For address 1234h, enter 34h.
„ Data Quantity: Enter the quantity of data to either read or write. Each register contains 2 data bytes. To read or write 1
register, enter 2. To read or write 2 registers, enter 4. For 6 word input/output messages, 2 is the only valid entry.
„ Data: All drive register data consists of 2 bytes. The most significant byte, the upper half, of the value is contained in Data #
MSB. The least significant byte, the lower half, is contained in Data # LSB. For reading data from the drive, these registers must
be set to 0. For writing data to the drive, enter the data in the order that it is to be written to the drive at consecutive addresses
starting with the address entered as the Starting Address. For 16 word input/output messages, if data is to be written to 2 registers,
enter the appropriate values into Data 1 and Data 2. Data 3 and Data 4 must contain 0.
z Data # MSB: To read drive data, set this value to 0. To write data, enter the most significant byte, the upper half, of the data
to be written. To write data 5678h, enter 56h. To write more than one register, valid for 16 word input/output messages only,
the registers must be consecutive starting with the address entered as the Starting Address.
z Data # LSB: To read drive data, set this value to 0. To write data, enter the least significant byte, the lower half, of the data
to be written. To write data 5678h, enter 78h. To write more than one register, valid for 16 word input/output messages only,
the registers must be consecutive starting with the address entered as the Starting Address.
„ Handshaking: Set the HS bit, the MSB, bit 7, of the command message handshaking byte to the same state as the HS bit ,
the MSB, bit 7, of the response message handshaking byte.
‹ Toggle the PROFIBUS-DP Master Handshake Bit
Toggle the command message Handshake MSB, the most significant bit, bit 7, to signal the drive that the command message contains a
valid parameter access section. Make sure that all data has been entered into the command message before setting this bit. It is advisable to
insert at least one processor scan between setting the command message and setting the handshake bit. Maintain the state of the HS bit until
another command is to be sent to the drive.
‹ Message Received By PROFIBUS-DP Option - Ignore All Response Data
To signify the receipt of the command message, the PROFIBUS-DP Option will set the response message handshaking HS bit to match the
state of the command message handshaking HS bit. Depending on the scan time of the PROFIBUS-DP Master and the interval between
reviewing response messages, the PROFIBUS-DP Master may not see this response.