Campbell Scientific CR1000 Measurement and Control System - Manual (Page 314)

Section 8. Operation
314
8.1.5.1 Pulse-Input Channels (P1 - P2)
Read More! Review pulse counter specifications at CR1000 Specifications
.
Review pulse counter programming in CRBasic Editor Help for the PulseCount()
instruction.
Dedicated pulse-input channels (P1 through P2), as shown in figure Pulse-Input
Channels
(p. 314),
can be configured to read high-frequency pulses, low-level ac
signals, or switch closures.
Note Input-channel expansion devices for all input types are available from
Campbell Scientific. Refer to Sensors and Peripherals for more information.
Caution Maximum input voltage on pulse channels P1 through P2 is ±20 V. If
pulse inputs of higher than ±20 V need to be measured, third-party external-signal
conditioners should be employed. Contact a Campbell Scientific applications
engineer if assistance is needed. Under no circumstances should voltages greater
than
±50 V be measured.
Figure 99: Pulse input channels