Campbell Hausfeld SDM-CAN Manuale Utente

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Section 5.  Using the RS232 Serial 
Diagnostics Port 
5.1 Connecting to the RS232 User Port 
The user communication port is a DCE configured, 9 pin RS232 port. The port 
automatically powers up  when it detects valid RS232 signals and shuts down after 
a period of inactivity. The SDM-CAN automatically detects the incoming baud 
rates in the range from 1200 to 115200 baud. It is configured to work with eight 
data bits, one start bit and stop bit and no parity. The pin out of the RS232 DCE 9 
pin ‘D’ plug is shown in Table 5-1. 
Table 5-1  RS232 Pin Out 
Pin Number 
RS232 function 
Direction of signal 
1 DCD 
input. 
2 RX 
input. 
3 TX  Output. 
4 DTR  Output. 
5 0V  Ground. 
6 DSR 
input. 
7 RTS  Output. 
8 CTS 
input. 
9 RI 
input. 
 
To connect the SDM-CAN to most computers use a NULL Modem cable. When 
you try to communicate with the SDM-CAN, first send at least three ‘Carriage 
Returns’ so the SDM-CAN can recognise the baud rate at which you are 
communicating. As soon as your baud rate has been detected, the SDM-CAN will 
return the prompt ‘CAN>’ to your terminal window. If you have just powered the 
SDM-CAN up, you must wait until the LED status flash has finished before you 
attempt to communicate. 
The User Command interface will accept a number of commands which allow the 
user to view CAN frames, view set-up and other debug tools. These commands 
are discussed below. 
5.2  Diagnostic Commands 
Most commands are sent in normal ASCII text. The interface is not case sensitive 
and supports backspace for correction of typing errors. Normally you would 
execute these commands from a PC which is running a terminal emulator such as 
Hyperterminal.  
Some parameters for the commands are normally entered in decimal base 10 
format, but you can also enter them in hex format if you precede the number with 
‘0x’. For example, 123456
10
 can be entered ‘as it is’ or, alternatively, in hex 
format 0x1e240
16
.  
5-1