Control Techniques UD70, User Manual

Page: 66 / 154

UD70
Issue code: 70nu2
6-6 Serial communications
Baud rate
The user can select a baud rate between 300 and 38400. The default is
4800. See setup parameters.
Addressing
Each unit on an
ANSI
communications bus must be given a unique identity or
address so that only the target
UD70
unit will respond. The address
comprises two parts:
•
The Group Address which is the first digit.
•
The Unit Address which is the second digit.
Both the group address and unit address have a range of 1 to 9. A group or
unit address of 0 is not allowed (addresses 01, 10, 20, etc. are invalid). The
reason for this is that
UD70
cards and some Drives can be grouped together
(up to 9 units per group), and a message can be sent over the
ANSI
communications bus to all units of the group. To address a particular
group, the unit address of zero (0) is used. For example, to address all units
of group 6 the full address will be 60.
An additional feature is that a message can be sent to all units of all groups
simultaneously using the address 00. This address can be used to send a
Start command to a group of Drives which are mechanically coupled
together to drive a conveyer line. All the Drives will then start
simultaneously.
Note
It is important to realize that when using group
addressing, the
UD70
cards will not acknowledge the
command. (If several cards try to reply at the same time,
they would cause meaningless data to appear on the serial
communications bus.)
For data integrity, the format of the transmitted address requires that each
digit of the two-digit address is repeated: the address of
UD70
number 23 is
sent as four characters, eg:
2 2 3 3
The serial address follows immediately after the first control character of
the message (
EOT
).
Parameter identification
All parameters are identified by four digits representing the menu and the
parameter number, but without the decimal point.
Example To send a message to menu 4, parameter 8, write 0408 (the leading
zero must be included)
To send a message to menu 18, parameter 11, write 1811
1811.