4.1.5 Turbine Pulse Inputs
With the optional mezzanine module (P148) for pulse inputs installed,
the I/O module supports four pulse inputs either independently or as
two pairs (“dual pulse mode”). Generally, the pulse inputs perform
dual pulse measurement, such as in turbine applications. In dual pulse
mode, you can enable level A or B pulse checking.
Each input has an input range of 1 Hz to 10 kHz. Each channel has live
integrity checking. If cabling faults develop or if the pre-amp power
fails, the software activates a configurable circuit fail alarm.
The electrical connection for these inputs depends on which DPR
mezzanine module is fitted to the I/O module. The dual mezzanine
module accepts pulse inputs from 3.5 Volts dc to 24 Volts dc, when
wired as shown in Figures 4-13 and 4-14. The module cannot accept
NAMUR or current mode preamps without external devices.
The mezzanine module can interface to a variety of preamps, including
the Mercury (formerly Spectra-Tek) F 106 and ST106, Instromet
MK15, Faure Herman FH71 2-wire, Faure Herman FH71 3-wire, ITT
Barton 818U, and Daniel 1838 Preamp.
Table 4-8 shows the dual pulse input pin connections.