15
4.2 Digital Personality Module (DPM)
The Digital Personality Module (DPM) replaces the functions provided by the digital interface box. The
DPM, which is roughly the size of a US postage stamp, is installed directly into the transducer head and
provides electronics for pulse shaping, digital recirculations, auto interrogation, and cable interfacing.
Figure 4-4
Excitation Pulse
The waveguide driver board detects a logic level excitation pulse from the DPM. If the device is external-
ly interrogated, an RS422 excitation pulse is fed from an external control system.
The Temposonics linear displacement measurement systems are available with either synchronous or
asynchronous options. These options are available by the configuration of three miniature rotary switches
(SW1, SW2 and SW3).
4.2.1 Synchronous (External Interrogating) Mode
In synchronous operation, an interrogation pulse is supplied to the linear displacement transducer
from an external counter module. After supplying the pulse, the counter module waits until the
recirculation electronics return a termination pulse, and then ends the cycle. The time between
the interrogation and termination pulses is proportional to the distance between the transducer
head assembly and the movable magnet.
In this synchronous mode, SW1 and SW2 are set to the hexadecimal value of the desired number
of recirculations plus 80 (i.e. 81 to FF hex or 129 to 255). SW1 is the least significant digit and
SW2 is the most significant digit. Permissible settings are 81 to FF corresponding to 1 to 127 recir-
culations.
SW3 is ignored in this mode.
To Next Page
Loading...
Need help?
General