Due to the high complexity related to error detection in PROFIBUS DP segments, analysis and test tools are nowadays indispensabe. NetTEST II integrates a complete physical cable test, which leaves nothing to be desired.

Most frequent errors, such as installation errors, short circuits, line or shielding breakages can be detected and resolved prior to actual operation – regardless of whether the DP Slaves are connected, disconnected, powered-on, or powered-off. NetTEST II detects the length and the wave impedance of the connected PROFIBUS cable.

A line check via NetTEST II at the beginning or end of each PROFIBUS DP segment runs in three steps:

1. Test without terminator: Both bus terminators must be switched off.
2. Test with one terminator: Bus terminator at the distant bus end must be switched on and powered.
3. Test with two terminators: Both of the bus terminators must be switched on and powered. In case the second bus terminator is powered via the PLC (active PROFIBUS Master), the bus disconnector included in the delivery package can be used for disconnecting the signal lines.

NetTEST II is capable of detecting and pinpointing the following errors:

• Short circuits between the signal lines A and B by stating the precise distance in metres
• Short circuits between the signal lines A or B and the shield by stating the precise distance in metres
• Signal line or shield rupture by stating the precise distance in metres
• Interchanged signal lines A-B
• Incorrect or missing bus terminators
• False position of bus terminators
• Non-permissible cable length
• False wave impedance of the bus line
• Wrong type of cable
• Reflections
• Poor transmission or reception levels
• Non-permissible branch
• Live List of the connected Slaves
• Ident numbers of the connected Slaves
• Signal level of the connected Slaves
• Baud rate detection and all over signal level of the running network

NetTEST II allows the adjustment of different sensivity levels up to the millivolt range. If even with the highest sensivity no errors are detected, this assumes a highest installation quality. In addition, NetTEST II also generates a Slave list, detailing the ident numbers of all operable DP Slaves and evaluating the transmission level of the RS485 interface. During normal operation with the PLC, transmission and reception levels can be checked for unacceptable values or reflections and the actual baud rate can be indicated. All results are filed in a detailed test record. Up to 20 detailed test records can be filed and printed on a standard PC without any additional software.