Advantech PCLD-8751, User Manual

Page: 24 / 28

PCLD-8751/8761/8762 User Manual 18
Chapter 3 Operations
3.1 Power Source Selection
PCLD-8751, PCLD-8761, and PCLD-8762 require a +5V power supply
for correct operation. When using the SCSI 68-pin connector, PCLD-
8751 and PCLD-8761 can be powered directly from the PCI bus by con-
necting CN1 to any Advantech PC-LabCard product. It is also possible to
connect external supplies to PCLD-8761 by connecting an external power
supply to terminal TB7. It is recommended to use an external power
source when more than 8 relay channels are operated. Correct connec-
tions are shown in section 2.2. However, the external power supply is
required for PCLD-8762 in any circumstance to ensure normal functions.
3.2 Control Logic
The preferred control logic can be defined by setting the on-board jumper
JP1 (PCLD-8751, PCLD-8761, and PCLD-8762) and JP2 (PCLD-8761).
The default setting the positive logic, which means logic "1" = device
activated. For input channels, when the inputs are activated, the DI chan-
nels will be TTL “1”. And for DO channels, the relay will operate for a
TTL high (+5V) on the input (common contact connected to NO contact).
The relay will release for a TTL low on the input (common contact con-
nected to NC contact).
On the other hand, when the jumper was set as negative logic, which
means logic "0" = device activated. For input channels, the relay will
operate for a TTL low (0V) on the input (common contact connected to
NO contact). The relay will release for a TTL high on the input (common
contact connected to NC contact).