Measurement Computing USB-PDISO8 - Manual (Page 14)

USB-PDISO8 User's Guide Functional Details
Table 3-4. Screw terminal pin out
Pin Signal Name Pin Signal Name
IP0A Input 0 terminal A IP4A Input 4 terminal A
IP0B Input 0 terminal B IP4B Input 4 terminal B
IP1A Input 1 terminal A IP5A Input 5 terminal A
IP1B Input 1 terminal B IP5B Input 5 terminal B
IP2A Input 2 terminal A IP6A Input 6 terminal A
IP2B Input 2 terminal B IP6B Input 6 terminal B
IP3A Input 3 terminal A IP7A Input 7 terminal A
IP3B Input 3 terminal B IP7B Input 7 terminal B
0-NC Relay 0 Normally Closed contact 4-NC Relay 4 Normally Closed contact
0-C Relay 0 Common contact 4-C Relay 4 Common contact
0-NO Relay 0 Normally Open contact 4-NO Relay 4 Normally Open contact
1-NC Relay 1 Normally Closed contact 5-NC Relay 5 Normally Closed contact
1-C Relay 1 Common contact 5-C Relay 5 Common contact
1-NO Relay 1 Normally Open contact 5-NO Relay 5 Normally Open contact
2-NC Relay 2 Normally Closed contact 6-NC Relay 6 Normally Closed contact
2-C Relay 2 Common contact 6-C Relay 6 Common contact
2-NO Relay 2 Normally Open contact 6-NO Relay 6 Normally Open contact
3-NC Relay 3 Normally Closed contact 7-NC Relay 7 Normally Closed contact
3-C Relay 3 Common contact 7-C Relay 7 Common contact
3-NO Relay 3 Normally Open contact 7-NO Relay 7 Normally Open contact
Relay contact terminals (0 - NC, C, N0 through 7- NC, C, N0)
Connect external devices to the relay contacts using the USB-PDISO8 board's 24 screw terminals. Each relay
has a normally closed (NC), common (C), and normally open (NO) contact.
Caution! Before connecting wires to the screw terminals, turn off the power to the USB-PDISO8, and make
sure that the signal wires do not contain live voltages.
Wire gauge
Use 12 AWG to 22 AWG wire to connect field devices. Properly insulate the wires to avoid any short circuit to
the other connections, ground, or other points on the board.
Caution!
Keep the length of stripped wire at a minimum to avoid a short to the enclosure!
When
connecting your field wiring to the screw terminals, use the strip gage on the terminal strip, or strip
to 5.5 - 7.0 mm (0.215" to 0.275") long.
Form C relay output
A schematic for Form C relay contacts is shown in . The Form C relay has a C, NO, and NC contact. Figure 3-4
Figure 3-4. Form C SPDT relay
ƒ When a (0) is written to the output bit, the C and NC are in contact.
ƒ When a (1) is written to the output bit, the C and NO are in contact.
3-4