Renishaw SP25M Installationsanleitung Seite 21

SP25M installation and integration guide
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Features of the AC3
An optional 16-bit or 8-bit ISA bus Interface in I/O space
An option to connect to a ΔT controller ﴾customer supplied wiring adaptor required﴿
Three measurement channels (p, q, r), with a resolution of 16 bits
6 software selectable operating modes
Hardware synchronisation of data acquisition in 5 of the operating modes
ISA bus interrupt on data acquisition (in mode 3)
Probe power supply protection with resettable fuses
Paged version identification at the AC3 board identification register
Integral measurement timer
Detection of a connected SP25M
Over-range input
ISA / ΔT bus interface
The AC3 address space is in I/O space when the ISA bus is selected. Accesses in memory space are not permitted. The bus interface can
operate with 8‐bit data ﴾bytes﴿ or 16‐bit data ﴾words﴿. Selection of the ISA/ ΔT busses, base address and 8/16‐bit modes are with selection
switches.
Measurement channels ﴾'p', 'q' and 'r'﴿
These have 16‐bit resolution. Each time the ACQUIRE bit ﴾bit '11' of register '13'﴿ is written to with a '1', or the appropriate synchronisation
hardware is activated, the SP25M axis deflections are acquired and presented in registers '5' to '0', and the time latched into registers '7' and
'6'.
Integral measurement event timer
This timer has a resolution of 256 microseconds and a maximum value of 16.78 seconds. The timer count register is updated every time the
SP25M deflections are acquired. The timer can be reset to zero when the RESET TIMER bit ﴾bit '8' of register '13'﴿ is written to with a '1'. If the
timer reaches its maximum count value of 65536, the TIMER OVERFLOW bit is set to '1'. This can be inspected by reading the AC3 status
register ﴾bit '5' of register '14'﴿. The TIMER OVERFLOW bit is reset to '0' when the timer is reset.
Detection of a connected SP25M
This is carried out automatically by the AC3. When the AC3 recognises that it is connected to an SP25M probe, it applies power to it. Software
can inspect whether a probe is fitted by first writing a '1' to the REQUEST SET PROBE PRESENT bit ﴾bit '10' of register '13'﴿, then reading the
PROBE PRESENT bit in the status register ﴾bit '4' of register '14'﴿. When the SP25M is removed, the PROBE PRESENT bit will be reset to '0'
automatically. This feature is included so that software can detect that a probe has been disconnected, then reconnected since the PROBE
PRESENT bit was last inspected.
Issued 12 2021
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