tension controller PFSA145 3BSE008884R1

tension controller PFSA145 3BSE008884R1

tension controller PFSA145 3BSE008884R1

When a PC is connected to the panel, the panel’s internal 0 V (GND) will be connected to the protective ground via the PC.
A number of USB devices can have the shield connected together with the  protective ground. Here, the panel’s 0 V (GND) is connected to the protective ground when, for example, a USB memory stick, keyboard or similar device is plugged in.
If a number of units are connected that have a 0 V and a ground connection, and these are connected to various grounding points, there is a substantial risk of Section 7 Additional Installation Tips Cable and Bus Termination RS485
3BSE043448R501 49 problems. Grounding currents go through communication cables, the rear plate of the controller, and internally in the operator panel, and can cause errors.
Use external units to improve communication and achieve galvanic isolation.
Westermo has good industry-standard insulators that are also insulated from the 24 V DC feed.
Cable and Bus Termination RS485
• Use shielded and twisted pair cable.
The pair capacitance may not exceed 52.5 pF/m and area at least 0.25 mm2 (AWG 24), if you want to use the maximum transfer distance and maximum transfer speed.
• 0 V, the reference voltage for communication should be included in the cabling. With two-way communication use two pairs; one pair for communication and one pair for 0 V.
• The shield must be grounded at one end. The other end is usually grounded, but with longer distances or when there is a difference in the ground potential, the shield should be connected to the ground via 0.1 uF/250 V plastic capacitor to prevent ground current in the braided shield.
A number of manufacturers recommend that the shield be grounded at each node.
Various manufacturers have different systems for bus termination. The RS485 standard does not describe how the “Fail Safe” function would be carried out, just that the system should be able to handle the error