Rockwell Automation SA500 AC Power Modules - Manual (Page 28)

3-4 SA500 Power Modules
Strobe input detection is enabled by setting bits 8 and/or 9 in UDC register 101/1101.
The resolver position can be sampled on the strobe input's rising edge, falling edge, or
both. Latched data is sent to the UDC module immediately before it is needed by the
UDC module for the next UDC task scan. Note that the PMI operating system detects
only one edge per UDC scan. If the programmer chooses to have the resolver position
sampled on both edges of the strobe’s input, the leading edge will be detected in one
scan and the falling edge in the next scan.
Position data measured using this method is placed in UDC register 216/1216 in the
format shown in either figure 3.1 or 3.2. Bit 8 of UDC register 201/1201 is set to
indicate that the strobe signal has been detected. This bit is set for only one scan to
allow a strobe to be detected every scan. The UDC task must check this bit each scan
to ensure the validity of the strobe data in register 216/1216. Bit 9 of register 201/1201
is set or cleared when the external strobe is detected and indicates whether the strobe
level was rising (1) or falling (0).
Figure 3.4 – External Strobe Input Circuit Timing Diagram
EXT. STROBE
INPUT
RESOLVER
POSITION
LATCH
COMMAND
24 V NOM
T
pw
T
d
T
d
T
per
T
d
- 250 m SEC TYP.
T
pw
- 300 m SEC MIN.
T
per
- 1000 m SEC MIN.