Table 5. Current Source and Sink Limits
Terminal
Limit
1
1
"Source" is positive amperage; "sink" is negative amperage (–).
2
Exceeding current limits will cause voltage output to become unstable. Voltage should stabilize
once current is again reduced to within stated limits.
3
A polyfuse is used to limit power. Result of overload is a voltage drop. To reset, disconnect
and allow circuit to cool. Operating at the current limit is OK so long a a little fluctuation can be
tolerated.
4
Polyfuse protected. See footnote 3.
5
Current is limited by a current limiting circuit, which holds the current at the maximum by
dropping the voltage when the load is too great.
7.5.1 Switched-Voltage Excitation
Three switched, analog-output (excitation) terminals (VX1 to VX3) operate under
program control to provide ±2500 mV dc excitation. Check the accuracy
specification of terminals configured for exctitation in CR1000 Specifications
(p.
97)
to understand their limitations. Specifications are applicable only for loads not
exceeding ±25 mA.
Read More Table Current Source and Sink Limits
(p. 103) has more information on
excitation load capacity.
CRBasic instructions that control voltage excitation include the following:
• BrFull()
• BrFull6W()
• BrHalf()
• BrHalf3W()
• BrHalf4W()
• ExciteV()
Note Square-wave ac excitation for use with polarizing bridge sensors is
configured with the RevEx parameter of the bridge instructions.
7.5.2 Continuous Regulated (5V Terminal)
The 5V terminal is regulated and remains near 5 Vdc (±4%) so long as the
CR1000 supply voltage remains above 9.6 Vdc. It is intended for power sensors
or devices requiring a 5 Vdc power supply. It is not intended as an excitation
source for bridge measurements. However, measurement of the 5V terminal
output, by means of jumpering to an analog input on the same CR1000), will
facilitate an accurate bridge measurement if 5V must be used.
Note Table Current Source and Sink Limits
(p. 103) has more information on
excitation load capacity.
7.5.3 Continuous Unregulated Voltage (12V Terminal)
Use 12V terminals to continuously power devices that require 12 Vdc. Voltage
104
To Next Page
Loading...
Need help?
General
