Sensoray 417 - Manual (Page 31)

Instruction Manual 30
Termination Boards
To simplify field wiring, sensors may be connected to optional Sensoray screw termination boards,
such as Models 7409TB, 7409TC or 7409TDIN. All of these termination boards are designed to
connect directly to Model 417 headers P1 and P2 by means of standard 40-conductor flat cables.
Markings— the above connector pinout table lists termination board (TB) markings for screw
terminations as they appear on a Model 7409TB. Example: channel 5 connects to the CH5 V+ and
V- terminals on the TB connected to P1. Another example: channel 28 connects to the CH4 I+ and
I- terminals on the TB connected to P2. ISAbus ground—labeled “S” on the 7409TB—connects to
the cable shield, if present.
Thermocouples
The positive thermocouple wire must be connected to the “+” terminal, and negative wire to the “-”
terminal. Regardless of thermocouple type, the negative wire is always colored red.
For best results, use either a grounded or isolated thermocouple. If the thermocouple is not
grounded or isolated, high common-mode voltages may be present that can disrupt measurement
accuracy or damage the 417 circuit board.
DC Voltage
DC voltage sources must be arranged so that the positive wire is connected to the “+” terminal, and
the negative wire to the “-” terminal:
If the voltage source is not referenced to ISAbus ground, connect either the “+” or “-” lead to “S”
to prevent high common-mode voltages.
+
–
S
RED
+
–
S
Voltage +
Voltage –