Service manual

March, 09 TTPM3 - Service Manual 17
3.3.5 Cutting
The DC-motor first turns in one direction to perform the cutting. The cam wheel
actuates the micro-switch sensor when the mechanism reaches its home position
again. At this moment, the motor is forced to a quick stop as the drive circuit for
turning the motor in the opposite direction is activated momentarily.
3.3.6 Communications interface
The TTPM3 communicates with the host through the RS232 serial interface. The
transfer rate is 115200 baud as default but can be set to other speeds with
parameter 1. Circuit U13 adapts the TTL-levels to RS232 levels.
The communication protocol is:
8 data bits
1 stop bit
No parity
RTS/CTS handshaking
The setting of parameters 2 and 6 affects the communication as follows:
n2 1 = RTS/CTS
2 = XON/XOFF
n6 1 = ACK/NAK (+ error code) enabled
0 = Disabled (silent)