9 Counter
Inputs
The SCADAPack 350 has three counter inputs, identified as Counter 0, 1 and 2. Two of the counter
inputs, Counter 1 and 2, are designed for millivolt level turbine meters. The third, Counter 0, is a
high level digital input for use with open collector/drain output amplifiers.
Refer to the appropriate software manual for information on using the SCADAPack 350 Counter
Inputs in application programs.
•
For TelePACE applications use the
CNTR Controller Counter Inputs
register assignment to
read the counters.
•
For ISaGRAF applications use the
cntrCtrl
I/O connection to read the controller board counters.
•
For C applications use the ioReadCounterSP2 function.
9.1
Counter Input 0
Counter Input 0 is used to count contact closures. The input circuitry includes a 1000-ohm resistor
from the counter input to the 5V power supply. Refer to
Figure 7: Counter Input Wiring
example of wiring to an open collector output.
5
4
3
2
1
0
1
2
P5 – Counters
GND
Turbine
Meter
Sensor
GND
Turbine
Meter
Amplifier
Consult manufacturer of
amplifier for wiring details.
J9 J10
J11 J12
1 2
1 2
Without external amplifier.
Internal amplifier.
With external amplifier.
Dry contact input.
Figure 7: Counter Input Wiring
Counter 1 is shown as a millivolt input with a direct connection to a turbine meter sensor. Note the
use of shielded wiring and that the shield is connected at one end only. Counter 2 is shown
connected to an external turbine meter pre-amplifier. Refer to the following sections for details on
connecting to the turbine meter counter inputs.
9.2
Turbine Meter Counter Inputs 1 and 2
The SCADAPack 350 allows for the direct connection of two turbine meter sensors. These sensors
produce millivolt outputs and do not required to be connected to an additional pre-amplifier when
connecting to a SCADAPack 350. The turbine meter inputs should be used in low noise
environments with shielded cabling.
SCADAPack 350 Hardware Manual
February 14, 2007
25
