Rockwell Automation 57C421B Pulsetach Input Module/DCS 5000/AutoMax - Manual (Page 59)

EĆ1
Appendix E
Module 57421Ć1, 57C421A, and 57C421B
Compatibility
Module 57C421A differs from module 57421Ć1 as follows:
D Channel A (terminals 12 to 14), channel B (terminals 15 to 17), and the Z
pulse (terminals 18 to 20) differential inputs are isolated. Input voltages
can range from 5 to 24V. An external series resistor must be used for
voltages in excess of 12V. The minimum voltage for a 5V input is TTL level.
D The input voltage range for a singleĆended input is 5 to 24V. An external
series resistor must be used for voltages in excess of 12V. The minimum
voltage for a 5V input is TTL level.
D The maximum input pulse frequency is 150 kHz.
D Terminal 1 is not connected to the module's internal circuitry. Module
57421Ć1 used this terminal as the external 12V power source for
singleĆended inputs.
D Terminal 5 is not connected to the module's internal circuitry. Module
57421Ć1 used this terminal as the common ground for the external 12V
power supply used with the singleĆended inputs.
D The upper byte of register 3 is the sign extension byte. Register 3 can be
directly assigned through the IODEF statement in the configuration task.
Register 3 and register 4 together form a 24Ćbit comparator.
D A 2 kHz timer mode is provided.
D The 24Ćbit counter can be programmed with a position feedback value
with programmable scanĆbased interrupts.
D Register 5, bit 13 Ć In the 57421Ć1 module, this bit was not used.
In the 57C421A module, this bit determines whether
the module is to used as a counter with pulsetach
inputs or as a timer using its internal 250 kHz clock.
Refer to section 4.2.4 for additional information.
D Register 5, bit 14 Ć In the 57421Ć1 module, this bit was not used.
In the 57C421A module, this bit determines whether or
not the counter register is cleared when an interrupt is
received. Refer to section 4.2.4 for additional
information.
D Register 6, bit 11 Ć In the 57421Ć1 module, this bit if equal to zero,
selected an optoĆisolated input. If equal to one, it
selected aline receiver input.
In the 57C421A module, this bit establishes the polarity
of the Z pulse input. If equal to zero, the Z pulse
polarity is positive. If equal to one, the Z pulse polarity
is negative.