18
RS232 serial communications
The extended command set offers the following advantages over the basic command set:
• Software control of the hand control unit (HCU1) functions such as jog and sweep
• Software control of selected PICS (product inter-connection system) functions such as probe
DAMPing, probe power OFF and LED OFF
• Software control of selected probe functions (TP200 probe reset)
• Common communications protocol for products using the extended command set
• As probing systems become increasingly sophisticated and offer a wider range of functions and
control options, they will be incorporated into the new command structure, reducing integration
times and costs for CMM manufacturers
• The introduction of product identifiers and device numbers will enable control of multiple Renishaw
interfaces in future implementations of the extended command set
Please refer to Renishaw for further details of the extended command set.
To select the extended command set mode and protocol, set switch 9 (command set selection) UP.
NOTE: The functions of switches 6, 7 and 8 will have no effect on the system when switch 9 is UP.
In extended command set mode, the data transmission and protocol formats are fixed in line with modem
RS232 conventions. There are no user selectable options.
Data transmission format is as follows:
1 start bit
7 data bits
1 even parity bit
1 stop bit
Protocol:
PHC10-2 RTS is normally asserted. It is unasserted when the PHC10-2 is unable to receive further
transmissions.
The PHC10-2 CTS must be asserted (by the CMM computer, or by linking DTR to CTS) to allow
the PHC10-2 to transmit.
XON/XOFF:
The extended command set supports the use of XON/XOFF flow control by the CMM computer.
If the PHC10-2 receives an XOFF character, PHC10-2 transmissions will cease and be buffered
until an XON character is received by the PHC10-2 or the output buffer overflows.
It is possible to continue transmissions to the PHC10-2 while it is in the XOFF state, although this is
not recommended as it may cause overflow of the output buffer, resulting in lost responses.
To Next Page
Loading...
