Parker Hannifin S.p.A. - Divisione S.B.C. LVD User’s Manual
77
In this case LUN=2, i.e. two bytes are transmitted for the data: the first byte is the mask
containing 0 in the positions of the bits to change and 1 in the positions of bits that must
remain unchanged; the second byte contains 1 in the positions of bits to be set to 1 and zeros
in the other positions. The address PAR corresponds to the parameter (byte) in which one or
more bits are to be modified. If the parameter is a word and the bit to be modified is among
the first 8 (b0...b7): PAR = parameter address; otherwise, if the bit to modify is one of the
upper 8 (b8...b15): PAR = parameter a 1.
[CMD7] = parameter write broadcast message to all drives connected to the serial line;
format:
[STX] [11100000] [LUN] [PAR] [D0]... [Dn] [CHK]
The peripheral device address (ADDR) must be zero.
Notes:
- Parameters shown on the display with decimals must be treated as integer values, e.g. 978.5
will be read, and written, as 9785.
- All values preceded by the symbol $ are hexadecimal numbers.
- The value in square brackets is the basic unit (byte) of the message.
- To be considered valid all messages must be terminated within a clearly defined time
interval (time-out) which is a function of speed, and they must have correct parity and
checksum.
- The drive responds to data requests or transmission only if the message is received
correctly; if the message contains an error, no answer will be transmitted. The only
exception is message type 7, with which a datum is transmitted with a single message
addressed to all drives connected to the serial line.
Serial line initialisation and management
Drive serial communication can be enabled or disabled by means of bit b40.14.
The drive is factory set with b40.14=0, i.e. serial line disabled (default). However, the
serial line is automatically enabled if the drive is disabled (b41.12=0).
If you want to use the serial line first set the baud-rate in Pr26, set the serial address in
Pr27, enable serial communication by setting b40.14=1 and finally, initialise serial comms
with command b42.3. At this point, save the configuration using command b99.15.
The drive address assignment could be automatically done following this procedure:
- connect the drives via serial link and power them on disabled
- set the binary code of the desired serial address for each drive using digital inputs 3, 4, 5
and 6; so you have 16 codes at disposal, digital input 3 is the least significant bit
- send the broadcast message to set the byte at the address 0x9C equal to 128, that is:
[$7E][$E0][$01][$9C][$80][$FD]
In this way each drive having Pr27=0 (default) set Pr27 equal to the code at its digital inputs,
set b40.14=1 and initialise the serial communication.
For parameter addresses and lengths refer to the relative table.
In the case of pico-PLC instructions, each one occupies 2 or 4 bytes, the format of which is
described below.