Vaisala DM500 - Manual (Page 76)

User's Guide ______________________________________________________________________
74 __________________________________________________________________ M210205EN-D
CAUTION
The dip switches behind the DMI500 MUST NOT be touched,
because the processor may be destroyed as a result of false dip switch
positions.
NOTE
Before connecting a PC to DMI500 or DMP501, make sure there is
no ground potential difference between PC and the DM500.
Serial Communication Settings
Connect the DM500 to PC by using a serial cable (provided). When
connecting EIA-232 (RS232), use the port called 'SERIAL'. When
connecting optional RS485, use the port called 'RS485/LON'. Connect
the RS485 as follows:
Table 2 4-Wire Connection
Terminal Data Line
1 R+ (input to DM500) ←
2 R- (input to DM500) ←
3 T+ (output from DM500) →
4 T- (output from DM500) →
5 Shield
Table 3 2-Wire Connection
Terminal Data Line
1 R/T+ connect the same line to
terminals 1 and 3
2 R/T- connect the same line to
terminals 2 and 4
3 R/T+ connect the same line to
terminals 1 and 3
4 R/T- connect the same line to
terminals 2 and 4
5 Shield
Select the DM500 communication mode and data transfer settings as
follows:
1. Open MENU : press .
2. Select ► Interfaces , press .