ABB PFEA 111 User Manual page 78

Tension Electronics PFEA111/112, User Manual
Chapter 6 Fault-tracing
6-6
Fault symptom
No signal when load is applied 1. Check that cables to the electronics are
Table 6-1. Fault Symptoms and Measures
correctly connected.
2. Check that the load cells are connected with
correct polarity. If not, the load cell signals cancel
out each other. This is displayed on the operator
panel as described below:
a. The sum signal (A+B) is low
b. The difference signal (A-B) is high
c. The output signal of the individual load cells
have opposite signs (polarity) when a force is
applied on the middle of the roll.
To check load cell signal polarity, see
Checking Load Cell Signal Polarity
For connecting the load cells to give positive
signals for increased web tension, see cable
diagram for the installed load cell type.
3. Switch off the tension electronics and measure
the cable resistance in the load cell signal circuit
between terminals X1:5 and X1:6 and between
X1:9 and X1:10.
a. The resistance is > 25 ohm:
Check cabling and load cells.
b. The resistance is < 25 ohm:
Check the mechanics.
Measures
Section 3.9
3BSE029380R0101 Rev C