Installation & Start-Up | 3-15
Figure 3-14.
RS-485 Cables, Multiple 3050ās
Notes:
1. Total cable length not to exceed 1000m. Cable should be low capacitance type for use in
RS-485 applications (nominal impedance of 120 ohms, shielded twisted pairs). For example,
Belden 9841 in two wire applications, Belden 9842 in four wire applications.
2. Install terminator plug (P/N 305900901) is RS-485 OUT position of last controller in
networks with both single and multiple 3050 analyzers.
3. Cable shields should be tied to TB3-GND at each 3050. If this is not possible (for example,
in the case of a ground loop), tie the shield at the PC or DCS to chassis and all other shields to
earth through a 0.1 uF @ 500V capacitor
4. Adding a jumper between pins 1 and 3 disables software control of the RS-485 mode. With
jumper installed, the 3050 will always be in four wire mode.