Allen-Bradley Guardmaster - Page 81

Rockwell Automation Publication 440R-UM013E-EN-P - March 2017 81
Troubleshooting Chapter 11
Figure 78 - Typical Connections to PowerFlex Drive
Figure 79 shows the test connections to verify the common reference between
the DIS safety relay and the AC Drive. Remove power from the application
and set the digital multimeter to ohms. If possible, measure directly at the
terminals. The resistance must be less than 1 ohm.
Figure 79 - Continuity Test of the Voltage Supply Common Connection
The OSSD test pulses of the DIS safety relay, as viewed by an oscilloscope, are
shown in Figure 80
and Figure 81 on page 82. Most often, the main transistor
triggers the scope; this test pulse appears on all four terminals simultaneously.
Step Description
1 The voltage at 34 must be slightly less than the supply voltage. If not, then the DIS relay must be
replaced.
2 The voltage at S2 must be slightly less than the supply voltage and must be the same as the voltage at
terminal 34. If not, check for an open circuit (broken wire) between terminal 34 and S2.
3 The voltage at terminal 4 must be zero. If not, check for an open circuit between terminal 4 and the
voltage supply ground connection. Figure 79
shows how to verify the continuity from terminal 4 of the
drive to terminal A2 of the DIS safety relay.
SHOCK HAZARD: Turn power OFF before continuity is tested.
34 44 14 24
S2
4
S1
PowerFlex 525
AC Drive
A1
A2
24V DC supply
24V common
23
Volts
DMM
1
2
3
OUT
Motor
34 44 14 24
S2
4
S1
PowerFlex 525
AC Drive
A1
A2
24V DC supply
24V common
OUT
Motor
<1
Ohms
DMM