Super Systems DAQ - Manual (Page 14)

Super Systems Inc. Page 14 of 34 DAQ Operations Manual
4 – 20 mA Current Loop Connections
Before connecting the current loop, insert the shorting jumper on the board for each channel
used to measure current loops. This jumper inserts the 62-ohm shunt resistor across the input
of the A/D. If multiple current loops are connected to one board, all must share the same power
supply and ground reference points or the accuracy of all the current loops need to be checked
for accuracy. When setting up a current input signal, such as a 4 – 20 mA signal, the jumper
must be placed on the pins in the current setup (right diagram). Notice that there is also a
jumper set up in the 1:1 setup only when inputting a current signal. This is because current
signals also have a corresponding voltage signal.
Warning: Connecting a mA input without the Input Jumper will damage the input.
To add a jumper to an input:
1. Power down the unit.
2. Remove the thermocouple connector and the Ethernet cable from the DAQ.
3. Remove the top plate of the DAQ by unscrewing the screws around the top of the DAQ.
4. Grasping both sides of the input board, carefully pull the input board out of the DAQ and set
the jumper for the appropriate set of pins, i.e. “V1” for input 1, “V2” for input 2, etc. A jumper
will need to be set – placed on both pins – to be considered “on”. Slide the input board back
into the DAQ slot.
5. Replace the top plate of the DAQ by screwing in the screws around the top of the DAQ.
6. Re-connect the Ethernet cable and thermocouple connector.
Setting the DIP Switches to Assign Board Numbers
Each input board, whether directly connected in the DAQ or connected through a satellite box,
must have a unique address assigned by the DIP switches on each input board. A unique
address will ensure that the DAQ will correctly read all of the boards set up. If two or more
boards have the same address, multiple errors could occur such as: DAQ reading data from one
board one second, then reading data from another board the next second, no data being read
from the DAQ, etc. It is important that each board has a unique address . Each DIP switch has
four switches on it labeled: 1, 2, 3, and 4. These numbers follow a binary numbering system –
i.e. 1 = 1, 2 = 2, 3 = 4, and 4 = 8. There is an ON and an OFF position for each switch. OFF = 0
and ON = 1. Each board number can be assigned by setting the appropriate switches to ON. For
example, to set a board number to 1, set the “1” switch to ON and the “2”, “3”, and “4” switches
to OFF ((1*1) + (2*0) + (4*0) + (8*0) = 1). To set the board number to 10, set the “1” and “3”
switches to OFF and the “2” and “4” switches to ON ((1*0) + (2*1) + (4*0) + (8*1) = 10). NOTE:
Turning all switches to the off position sets the board to address 16 .