4 - 10 External Switch Input Connection
4-12
● Internal circuit diagram of the DCP552 connecting external switch input
Handling Precautions
• The inputs of the DCP552 unit are provided with a built-in power supply
(open voltage type, 8.5V DC). Always use no-voltage contacts
externally.
• For the no-voltage contacts, use gold contacts or other relays that switch
on small currents. Other types of relay contacts may not switch. Use
contacts that have ample margin over the minimum switching capacity
with respect to the current and open voltage ratings of contacts provided
on the DCP552.
• If using semiconductors (open collectors, etc.) as no-voltage contacts,
use one that maintains a potential of no more than 2V across the
contacts when actuated, and a leakage current of no more than 0.1mA
when shut off.
• The digital inputs (remote switch inputs) of all SDC40 and SDC10 series
units can be connected in parallel. If connecting them in parallel to
another instrument, carefully check the requirements of the other
instrument before proceeding.
• Do not connect SDC20/21, SDC30/31 series in parallel. Doing so may
cause the external switch input to malfunction.
• Common terminals (12) and (41) of the external switch input are
connected internally.
