Control Techniques Digitax ST - Page 65

Parameter
structure
Keypad and
display
Parameter x.00
Parameter
description format
Advanced parameter
descriptions
Serial comms
protocol
Electronic
nameplate
Performance
Menu 3
Digitax ST Advanced User Guide 65
Issue Number: 1 www.controltechniques.com
As bit 14 of the second word is set to one the drive will add the checksum and transfer this message to the encoder. When the encoder response has
been received by the drive the first byte of the message will be placed in the least significant byte of Pr 90.23 and bit 15 will be set to one. This data
should be read and the parameter cleared so that the drive will put the next byte into this parameter. The sequence of data that should appear in
Pr 90.23 for an encoder with an address of 0x40 and a position of 0x03, 0x59, 0x63, 0x97 is shown in the table below.
Example of Hiperface transfer: Delete data field
Transfer the "delete data field" message to the encoder comms buffer by writing the sequence of words shown in the table below to Pr 90.22. A check
should be carried out before each word is written to ensure that the parameter is zero (i.e. the drive has taken any previous data).
The response from the encoder is a follows.
SC.EnDat
The Heidenhain EnDat protocol is a synchronous protocol using the following command message format (drive to encoder).
The following commands are supported:
Bit 15 Bit 14 Bit 13 Data
0xa0ff 1 0 1 0xff Broadcast message so address = 0xff
0xc042 1 1 0 0x42 Read position command
Bit 15 Bit 14 Bit 13 Data
0x8040 1 0 0 0x40 Encoder address
0x8042 1 0 0 0x42 Read position command
0x8003 1 0 0 0x03 Position byte 0 (MS byte)
0x8059 1 0 0 0x59 Position byte 1
0x8063 1 0 0 0x63 Position byte 2
0x8097 1 0 0 0x97 Position byte 3 (LS byte)
0xc0ac 1 1 0 0xac Checksum
Bit 15 Bit 14 Bit 13 Data
0xa0ff 1 0 1 0xff Broadcast message so address = 0xff
0x804d 1 0 0 0x4d Create data field command
0x8002 1 0 0 0x02 Data field 2
0x8065 1 0 0 0x65
Status of data existing data field 2 with bit 7
set to zero
0x8055 1 1 0 0x55 Code for data field at default of 0x55
Bit 15 Bit 14 Bit 13 Data
0x8040 1 0 0 0x40 Encoder address
0x8042 1 0 0 0x4d Create data field command
0x8003 1 0 0 0x02 Data field 2
0x8059 1 0 0 0x65 Status of the data field before delete
0x8063 1 1 0 0x78 Checksum
Command
1
st
byte
Address
Data (LSB)
Data (MSB)
4
th
byte
Code Command Address Data
0x00 Encoder to send position Don’t care Don’t care
0x01 Selection of memory area MRS code Don’t care
0x03 Encoder to receive parameter Address Data
0x04 Encoder to send parameter Address Don’t care
0x05 Encoder to receive reset Don’t care Don’t care