Question:
How are relays used with the User and Remote Port?
What applications are typically used for this?
Are there commercially available switch boxes for this purpose?
Answer:
1. The Remote Port
The Remote Port connector on the ATi is different from the one on the AT3600. The ATi has a 15 pin D Connector, the AT3600 has a 9 pin D connector. The functionality of both is the same but their pin allocations are different. The ATi Remote connector has an additional 12V output that can be used as a power source for relays.
Please find the attached pin out diagrams for the AT3600 and the ATi.
The remote port is used to control the overall function of a program. This is the interface that may be used to connect to a programmable controller or for simple switches and indicators.
There are two inputs and three outputs:
Inputs
RUN - Used to start a test program when the transformer is in place ready to test. Commonly used with a footswitch. The !RUN input is an active Lo input with an internal pull-up resistor.
In the execution of programs, it is equivalent to pressing the RUN key on the front panel. To use this with a footswitch, wire the switch between this input and 0V.
STOP - Used to stop the program during a test. See also the safety interlock port. The !STOP input is an active Lo input with an internal pull-up resistor. The active-going edge of this input halts all Tester activity, turning off all signal sources. To use this with an emergency stop switch, wire the switch between this input and 0V.
Outputs
BUSY - Mimics the front panel busy indicator and is used to indicate a program is running. Yellow in a traffic light indicator.
PASS - Mimics the front panel pass indicator. The results of every test in the last program run were 'pass'. Green in a traffic light indicator.
FAIL - Mimics the front panel fail indicator. One or more of the tests in the last program run were 'fail'. Red in a traffic light indicator.
Beep Output- This is an active Hi output that copies the internal beeper.
The remote output port hardware is TTL logic level compatible and is fitted with 1kOhm protection resistors in series with each output. This is ideal for most programmable controllers.
To control power devices such as lamps directly you will need to interface the remote port to drive relays.
Driving Relays from the Remote Port:
The remote port outputs are TTL compatible and protected with 1 kohm series resistors.
This means that less than 0.5mA can be reliably sourced from these outputs.
The 5V supply (pin 5) is protected with a 75 ohm resistor so less than 10mA should be drawn to avoid excessive voltage drop. To drive relays from the remote port outputs, a buffer of some type is required.
Example:
A common example of a buffer IC is the Motorola MC14049. This consists of six buffers. The remote port will comfortably drive the inputs of these buffers. The outputs will source 20mA or more, but will more reliably sink current of 70mA or more.
The chip can be powered at up to 18V, thus for the the AT3600, the USER port 12V power may be used. The ATi Remote port has a 12V source (pin 3). Note that remote port power is limited. To make the most of the AT3600 or ATi available power and the IC's sink ability connect in the following way:
Take the required remote port output and pass it thro 2 buffers in series.
For the AT3600:
REMOTE pin 2 (PASS) to pin 3 of the IC. Connect pin 2 to pin 5.
Now pin 4 is a buffered duplicate of remote port pin 2.
Supply the IC pin 1 with +12V from the USER port pin 5.
Common OV: REMOTE port pins 7 and 8 connected to IC pin 8.
Connect a 12V relay (min coil resistance say 150 ohm) between IC pin 4 and +12V.
Fit diode protection across the relay as normal. (Cathode to +12V).
For the ATi:
REMOTE pin 10 (PASS) to pin 3 of the IC. Connect pin 2 to pin 5.
Now pin 4 is a buffered duplicate of remote port pin 2.
Supply the IC pin 1 with +12V from pin 3.
Common OV: REMOTE port pins 2, 6 and 13 connected to IC pin 8.
Connect a 12V relay (min coil resistance say 150 Ohm) between IC pin 4 and +12V.
Fit diode protection across the relay as normal. (Cathode to +12V).
Please see the attached data sheet for the Motorola MC14049.
2. The User Port
This is described in detail in the attached Applications note entitled “Using the AT Series User Port” VPN 104-112
This document discusses the use of connected relays and the operation of the OUT test to control relays.
Please note, the User port in conjunction with relays and OUT tests may be used for connecting windings in series for certain tests.
This document applies to both the AT3600 and the ATi.
3. Commercially available relay switch boxes
These are available from Kust in Germany and Wilco Controls in the US. Please see the attachment entitled Commercially available relay boxes. These products are not CE or UL certified.
4. Case Study
Please find attached files “AC Interface connection to two transformers” and an AT3600 test program “OUT TEST.atp”. This is a case study where the user has two transformers which have a MAGX and VOCX test requirements on each transformer. To achieve this without manual intervention an OUT test is used as follows.
This test requires an AC Interface (500V test voltage) and the AC Interface output must be switched with relays between the two different transformers. Note that the AC Interface has only one output and this requires relays to switch this output to each transformer. The OUT test (see the .atp program) is applied to switch outputs 0 and 1 first, then 2 and 3. Finally at the end of the program an OUT test switches off all relays 1 to 3.
Note ESD, ESE and power amplifier connections are not shown in the connection diagram for simplicity.