Serial Communication - JVL MAC050 User Manual

5.10
5.10.1 Controlling the MAC motors and MAC00-xx modules using serial com-
munications.
Introduction:
This chapter provides information on the operations that can be performed over serial
lines, either RS-232 or RS-485. In addition to regular register reads and writes, a number
of typical operations like Reset and Save in Flash memory is described.
Additionally, this chapter describes how the MacTalk Windows™ program performs
some of the more special operations available from the MacTalk program menus and
buttons.
General information:
There are two serial channels to the basic MAC motors. One of them always uses the
MacTalk protocol and the other one always uses the FastMac protocol.
Communications can be used simultaneously on both channels.
The FastMac channel is a point-to-point connection where there can be only one client
communicating with the basic motor, while the MacTalk channel can be used to connect
several motors to one controlling computer or PLC.
The FastMac channel consists of two sets of differential signals, one for data sent to the
motor and one for data sent from the motor. This provides a high degree of noise immu-
nity which allows the protocol to have less overhead for error checking and thus work
very fast.
Both of these protocols use binary data rather than text data. It is not possible to use a
text terminal program like Windows Hyper Terminal to communicate on any of these
protocols.
Depending on the type of MAC00-xx module mounted on the motor, the MacTalk chan-
nel can be made available as RS-232 or RS-485 and on the wireless modules as a Blue-
Tooth serial port or a virtual COM port over TCP/IP.
Note that the MAC00-xx modules drive the RS-232 and RS-485 lines in a slightly non-
standard way, which must be taken into account. This is described in detail elsewhere in
this manual, but the overall differences are that, for RS-485, the modules drive the line in
transmission mode up to approximately 560 micro-seconds longer than necessary and
for RS-232, the TxD line is only driven actively high, while it must be pulled passively low
by a resistor (provided on the module and selectable via a DIP-switch). This special non-
standard RS-232 coupling allows several motors to be connected to a single controlling
computer or PLC, much like RS-485.
The MAC motors can be mounted with either 'intelligent' MAC00-xx modules that have
an integrated processor to handle the communications to the basic motor or they can be
mounted with 'dummy' modules that just do minimal hardware translation of the signals
but allows the user access to the FastMac protocol.
When mounted with 'intelligent' modules, the MacTalk channel is shared between the
modules and the basic motor. This means that data received on the module interface will
be received by both the module and the motor at the same time, while data sent from
either the module or the motor will be combined in hardware and sent via the module
interface (connectors or cables).
276 JVL Industri Elektronik A/S - User Manual - Integrated Servo Motors MAC050 - 800

Serial communication