39
Conflicting Parameters
D
If the commanded velocity is too high
and/or the Maximum Position Error is
set too low, it is possible to trip the
‘Maximum Position Error’ (Error bit I/O
address 235 or 243 set on – see
Section 5.5). If this is the case, set the
Maximum Position Error to a much
larger value – reset the error (in Run
mode), then tune the axis according to
Appendix A. After the axis is tuned,
reduce the Maximum Position Error to
an acceptable number.
D
It is possible to trip the ‘Maximum
Position Error’ with a seemingly
acceptable acceleration or velocity
command if the axis gains are too low.
Refer to Appendix A.
Motion Not Controlled Well
When dealing with erratic operation, in
most instances it is due to stray signals
from EMI or RFI sources entering the
controller. Be sure all signals are
shielded correctly and grounds are
installed according to the
recommendations described in SMC20
Installation section (page ##).
When dealing with unacceptable
accuracies, repeatabilities, or long cycle
times, and you are confident the
components of the control system have
been selected and installed correctly, it
is most probable that greater attention
must be paid to the tuning of the axes.
Refer to Appendix A.
General Faults
The following addresses are dedicated
to error tracking in the SMC20 and other
versions utilizing the Hand-Held
Terminal:
Address
Error Condition
232 – Over for Axis #2
233 – Over travel – for Axis #2
234 – Profile select error for Axis #2
235 – Maximum position error for Axis #2
236 – Profile segment error for Axis #2
237 – Position sensor error for Axis #2
238 – DSP error for Axis #2
239 – Spare error bit for Axis #2
240 – Over for Axis #1
241 – Over travel – for Axis #1
242 – Profile select error for Axis #1
243 – Maximum position error for Axis #1
244 – Profile segment error for Axis #1
245 – Position sensor error for Axis #1
246 – DSP error for Axis #1
247 – Spare error bit for Axis #1
You could assign one of these to an
output, for example, to know
immediately when that error has
occurred.
Use the Monitor mode to view these
addresses to see what caused the error.
The cause of error can be quickly
viewed in the Monitor mode – Alarm
screen:
AXIS[ 1] ALARMS
↑
F1
FLAGS(00010000)
F2
↑
←
F3
9MAX POS ERROR)
↓
→
F4
In this example, the “1” represents a
Maximum Position Error. Each “Bit”
represents a possible error. 0 = No
Error, 1 = Error. Use F3, F4 to scroll
across them to display a message on
the error flags meaning.
List Function Inoperative
The List Function sends a printer ready
listing of the selected parameters
through the RS232C port.
If List is not working, use the following
procedure to diagnose the problem.
1. Verify the printer cable is connected
to the printer’s serial port. Most
printers have both serial and parallel
ports.
2. Verify the printer is set up for 9600
baud.
9600 baud, 8 data bits, 1 stop bit,
no parity
3. Try switching pins 2 & 3 on one end
of the cable.
4. Verify cable construction. Check for
shorted pins and continuity. See
Table 2-6. RX, TX, and COM are the
only signals needed.
