Measurement Computing CIO-DO24DD - Manual (Page 11)

Figure 4-2. Darlington Output Circuit
All outputs share a com mon ground on the board so all your circuits must use the
common ground. Also, as with any transistor circuit, there is a small amount of OFF
current.
4.5 PULL-UP RESISTORS
There are locations for pull-up resistors on the board. They are marked RN1 through
RN3 (through RN6 on the CIO-DO48DD).
These locations are designed to accept 9 pin SIP resistors configured as eig ht
individual resistors with one end in common. Each resistor in the SIP package makes
a connection between one of the Darlington collectors and the pin labeled “Pull Up #”
for the port associated with that particular Darlington transistor.
For example, installing a 9 pin SIP resistor into the location marked “RN1” places a
resistor between all of the Darlington collectors for Port A1 and the pin labeled “Pull
Up 1”. A voltage applied to this pin becomes the supply voltage for all eight of the
Darlington transistors in Port A1.
4.6 SIGNAL CONNECTION
The output circuits are capable of completing a circuit of up to 50 volts and having a
current of up to 500 mA.
1. The voltage specification applies only when the transistor is off. The
transistor can block up to 50V.
7