Campbell CR6 Series, Operator'S Manual

Page: 124 / 690

Section 6. Specifications
124
6.6 Dedicated Power Output Terminals — Specifications
Three terminals, 12V , SW12-1 , and SW12-2 , provide nominal 12 Vdc power to
external devices such as peripherals, sensors, or telecommunication equipment.
Voltage output is 0.3 Vdc less than voltage at BAT terminal.
Current sourcing limits for power output terminals are summarized in Omnibus
Current Source and Sink Limits — Specifications
(p. 124).
6.7 Omnibus Current Source and Sink Limits — Specifications
Power output terminals include U , C , 12V , and SW12 terminals. Each is
discussed in its own section in these specifications. The following table
summarizes the limits of these power output terminals:
CR6 Power Out Limits
1
: U, C, CS I/O
Terminal
Voltage
Excitation
Current
Excitation 5 V Logic Level 3.3 V Logic Level
Max
Current @
±2500 mV
2
Max
Current
Output
Resistance
(R
o
)
Max
Current
@ 3.5 V
3,4
Output
Resistance
(R
o
)
Max
Current
@ 1.85 V
3,4
C1 , C2 ,
C3 , C4
See following
graphs
150 Ω 10 mA 145 Ω 10 mA
U1 , U3 , U5 ,
U7 , U9 ,
U11
±25 mA ±2500 µA 75 Ω 20 mA 73 Ω 20 mA
U2 , U4 , U6 ,
U8 , U10 ,
U12
±25 mA ±2500 µA 150 Ω 10 mA 145 Ω 10 mA
CS I/O Pin
1
200 mA
1
"Source" is positive amperage; "sink" is negative amperage (–).
2
Exceeding current limits causes voltage output to become unstable. Voltage should stabilize once current is again
reduced to within stated limits.
3
A thermal fuse limit current. Circuit holds current at the maximum by dropping the voltage when the load is too
great. 5 Vdc on U terminals will drop to 3.5 Vdc when sourcing 15 mA. 5 Vdc on C terminals will drop to 3.5 Vdc
when sourcing 8 mA. To reset, disconnect and allow circuit to cool. Operating at the current limit is OK so long some
fluctuation can be tolerated.
4
Drive capacity is determined by the logic level of the Vdc supply and the output resistance (R
o
) of the terminal. It is
expressed as: V
o
= 4.9 V – (R
o
• I
o
), where V
o
is the drive limit, and I
o
is the current required by the external device.