Input connections are labeled "+", "GND", and "-". Shields should be connected to the "GND" terminal if not grounded at the sensor end. Three-wire RTD connections can be made as follows: connect RTD wires +V and +I to the "+" terminal on the AIM-16, connect RTD wire -V to the "-" terminal, and connect RTD wire -I to the "GND" terminal. To assure that there is minimum susceptibility to EMI, proper EMI cabling techniques (twisted-pair wiring and, in extreme cases shielded wiring) must be used on input wiring.
If the precision 10V reference voltage from the A/D converter is to be used by external circuits, make connections to the two-position screw terminal labeled REF OUT. Then, connect a cable between the 37-pin connector on the card and the A/D converter.
As many as eight AIM-16 cards, or 128 channels may be serviced by one analog-to-digital converter card. The AIM-16 cards in the system are "daisy-chained" together by 37-conductor ribbon cables plugged on each card to two parallel 37-pin Sub-D connectors. The address of the AIM-16 card is established by selecting an output channel via a jumper installed at location OV0 to OV7.
The ribbon cable that interconnects AIM-16 to the AD12-8 also provides computer power (via the AD12-8) to the AIM-16. If Option P is installed on your AIM-16(s), 5V computer power is used by that option to generate isolated ±15V for the analog circuits on AIM-16 (Otherwise, ±12V computer power is used.). Since each AIM-16 can draw up to 125mA of current when Option P is installed, it is desirable to keep the total cable length from the A/D to the furthest AIM-16 as short as possible. You can tell if Option P is installed on your AIM-16(s) by looking at the lower-left quadrant of the board. If Option P is not installed, then there will be components absent in that area. If long cable length is required, you can use an external +5VDC power supply and locate it close to the AIM-16 to be powered. This, of course, will necessitate disconnecting the +5VDC computer power.
Also, if Option P is included on your card, it is desirable to have no more than three AIM-16s in any one "chain"; particularly if the REF OUT voltage is to be used as excitation for sensors. For applications where multiple AIM-16s are to be used, CAB37-18Y cables can be used. That cable provides ability to branch to two other AIM-16s. For example, consider the case where five AIM-16s are needed. In this case two CAB37-18Y and one CAB37-18 can be used as shown below.
