IEEE_488 to 4 Relay Drivers Box ------------------------------------ Original Rev. 17-JULY-2001 Current Rev. 17-JULY-2001 This box uses the old original ICS 4823A circuit board and has 4 relay driver outputs. The relay drivers are inverting, i.e. 75452 IC's. The box includes diode protection for the driver outputs and a 3 Amp fuse on the +5 Volt external supply. The wiring and pinout of the 15 pin "D" connector was setup to match the similar function on the "Digital Box" that is part of the full current sweep system. 15 Pin "D" Connector Pinout on the IEEE to 4 Relay Driver Box --------------------------------- Pin Function --- ---------------------- 3 +5 Volt 4 Relay Driver "B" 5 +5 Volt 6 Relay Driver "C" 7 +5 Volt 8 Relay Driver "D" 9 +5 Volt 10 Relay Driver "E" 1,2, 11:15 No Connection to these pins The following map of what 15 Pin "D" Connector Pin is controlled by what output signal from the IEEE Card and thus controlled by what Character and Bit in the Software Control Program. IEEE to 4 Relay Driver Box 15 Pin "D" Connector Pinout ICS 4823A Connection Relay Driver Outputs ------------------------------------------------- -------------------- Signal Programming Pin Relay Driver Pin Name Signal Function Character Bit ---- -------------- --- ------ --------------- ----------- ----- 4 Relay Drv "B" A14 Ch_13 1 \ Character 4 Bit 1 6 Relay Drv "C" B14 Ch_14 2 | MSD-3 Character 4 Bit 2 8 Relay Drv "D" A15 Ch_15 4 | Nibble Character 4 Bit 4 10 Relay Drv "E" B15 Ch_16 8 / Character 4 Bit 8 NOTES: 1. It appears that all the IEEE to Relay Driver Outputs in the various boxes are now using inverting drivers, i.e. 75452 chips, but that some of the documentation still says that these are setup with non-inverting drivers, i.e. 75451 chips. 2. At one time there was a problem with the old original ICS 4823A circuit board occasionally hanging the IEEE bus when certain bus controller cards or PC's were used to run the bus. If this happens again, the plan is to copy the firmware EPROM from the new ICS 4823A card and try that firmware in the old original card. I believe that the two ICS 4823A are exactly alike in all other ways. Update 12-FEB-2002 ---------------------- About a week ago the "IEEE_488 to 4 Relay Drivers Box" started to cause trouble on the IEEE Bus. You could write to this box OK and its outputs would change state but you could not read reasonable data from other devices on the bus and if you asked for the status of the bus you read in junk. Because another source of IEEE controllable TTL signals is available (from a Keithley instrument) the only thing that is really needed in this box is its Relay Drivers. To facilitate using an external input to the Relay Drivers a barrier strip was added to the back of the box. This barrier strip presents the outputs of the ICS IEEE card on the left and the inputs to the Relay Drivers on the right. So you can run jumper wires across to connect these or use an external source to control the Relay Drivers. View Looking at the Barrier Strip on the Back of the Box -------------------------------------------------------- ICS 4823A Card Relay Driver Outputs Inputs ---------------- ---------------- X X X X X X X X X X | | | | | | | | | | <-- Barrier Strip X X X X X X X X X X B R Y G B B B R Y G L E L R L L L E L R <-- Wire Color K D L N K K K D L N Common B C D E <-- Relay Driver +-> 1 2 4 8 Ground | 4 6 8 10 <-- Controls +-- Bit in the 4th Output Pin Programming Number on Character Sent the 15 pin to the ICS IEEE Card Connector The following table shows what 15 Pin "D" Connector Pin is controlled by what output signal from the IEEE Card and what wire color is used on the Barrier Strip to patch this signal from the IEEE Card to the Relay Driver. IEEE to 4 Relay Driver Box 15 Pin "D" ICS 4823A Card Connection Connector Pinout Barrier ----------------------------------------- Relay Driver Outputs Strip Signal Programming -------------------- Wire Pin Name Signal Function Chrctr Bit Pin Relay Driver Color --- ------ --------------- ------ --- --- -------------- ------- A14 Ch_13 1 \ 4 1 4 Relay Drv "B" Black B14 Ch_14 2 | MSD-3 4 2 6 Relay Drv "C" Red A15 Ch_15 4 | Nibble 4 4 8 Relay Drv "D" Yellow B15 Ch_16 8 / 4 8 10 Relay Drv "E" Green Notes from working on the "IEEE_488 to 4 Relay Drivers Box" on 11,12-FEB-02 1. The flat cable that connects the ICS 4823A Card to its "connector & switch" circuit board was coming loose from the "connector & switch" circuit board. It was coming loose from its pin #26 end, i.e. its single ground connection end. I did not have a replacement board mount connector of the required type so I removed the connector and hand soldered the cable to the "connector & switch" circuit board. 2. The connector at the ICS 4823A Card end of the cable that connects to the "connector & switch" circuit board was broken (strain relief) so I replaced this standard 26 pin connector. 3. The 96 pin DIN header that plugs into the ICS 4823A Card had pins A2, A3, B3 all connected. This was a mistake. What should be connected is B2 --> A3, B3 i.e. Device Trigger Pulse Output to Ch #1 External Data Ready and to Ch #2 External Data Ready. I fixed this so that now B2, A3, B3 are connected. A2 is the Reset Signal Input. All of this is just in case you ever would want to use this card to read something. For details see the section near the end of _ about readback: www.pa.msu.edu/~edmunds/i_source/i_source_sept_1999_digital_box.txt 4. Before working on the box, at power up: the PWR LED would come on and the RDY LED would make a single fast flash. After working on the box this behavior remained the same. 5. Before I have seen DIP switches of "a certain age" start to have flaky contacts. So I cycled all keys of this DIP switch. 6. Setting the DIP Switch Besides controlling the IEEE Bus Address, the DIP switch has 3 other keys that do something: Talk Only (key 6), Listen Only (key 7), and SRQ Inhibit (key 8). I assume that we can run this card as Listen Only. For Listen Only the book says, "set the Listen Only Enable input to ground and the Talk Only Enable input to open". The common side of the DIP switch is at ground so this means, Listen Only key 7 is Closed aka ON, and Talk Only key 6 is Open aka OFF. I assume that we do not want Service Request Interrupts from this card so that we could Inhibit SQR's. To do this the book says, "To inhibit the SQR message, ground the SQR Enable input". The common side of the DIP switch is ground so this means that SRQ Inhibit (key 8) could be set Closed aka ON and thus inhibit the possibility of this card generating a SRQ. Update 1-APR-2002 ---------------------- Add a 5.6 K Ohm pull up to +5 to the input to Relay Driver "C".