Here we illustrate a control system with 6 Control Circuits. The first two circuits control motors; each of these circuits requires a pair of Output Channels programmed for momentary action (start-stop). The next two circuits handle heating elements controlled by a time-switch; the last two control external loads. The last four circuits must be programmed for continuous contact action.

In Figure 3, a box located next to each circuit summarizes all necessary programming information.

The first information box (reference line 01) shows "pair of channels set for momentary action, with the contact of the first channel normally open (NO) and the contact of the second normally closed (NC). The Auto-Off option is needed for this Control Circuit". This circuit therefore takes up Output Channels 1 and 2. According to the second box (reference line 06) the second Control Circuit serving the other motor is like the first and utilises Output Channels 3 and 4. The third box (on reference line 11, at right) shows what is required for the next two Control Circuits which use two Output Channels programmed for continuous action. Both of these circuits are NO and one uses channel 5, while the other uses channel 6. Of these circuits, only the first one requires the Auto-Off feature. The next two Output Channels are identical to numbers 5.

Programming the IND-8, for this example, is done as follows:

According to table 4.12, Mode 3 is the correct one. With the IND-8 de-energized, the contact position of each of the eight channels will be as indicated in the table:

Control Circuit 1 2 3 4 5 6
Output Channel 1 2 3 4 5 6 7 8
On the telephone keypad, press 0 1 0 1 0 0 0 0
Contacts programmed to be: NO NC NO NC NO NO NO NO
Load Motor 1 Motor 2 heating Element External circuits
Auto-Off yes yes yes no yes yes

As Auto-Off is essential in the case of all Control Circuits except #4, programming this option, according to the sequence of these circuits, will require pressing the following commands on the telephone keypad.

(Keypad inputs)
1 1 1 0 1 1

9.1 Summary of Programming Action

For the reader's convenience we now tabulate all programming steps as per our example. Refer to sections 4.2 through 4.12 and enter the following data in sequence:

New Access Code (User's choice of 4 digits) 1 9 8 9        
New Master Code (choice of 7 digits) 1 2 3 4 5 6 7  
Number of rings (choose from 1 to 9) 4              
Mode (one of 5 available, see 4.12) 3              
Contact position with the device de-energized (0 = NO, 1 = NC) 0 1 0 1 0 1 0 1
Auto-Off function (0 = No, 1 = Yes) 1 1 1 0 1 1

The Mode chosen puts an automatic end to programming at this point.

9.2 Connections to the IND-8 for the example shown in Fig.3

Keeping in mind the example under discussion, please refer to Fig. 4. The feedback terminals of channels 2 and 4 (S2+ and S4+) are not connected. Channels 1 and 2 function as a pair and serve a single Control Circuit. This is why only one feedback channel is needed, connected to No 1. The same applies to the second pair of channels. The remaining 4 Output Channels each have one active feedback channel for monitoring their respective loads.

9.3 Exercise

To help the reader understand the operation of the IND-8 the following simulation may be found useful. Make no connections to output and input channels. Refer to Fig. 3 and 4.

9.3.1Hook up the secondary of the transformer to AC1 and AC2.
Connect the IND-8 to a telephone line. Make no other connections. Program the unit as per 4.3 through 4.11 using the data in the example of 9.1 as a guide.

9.3.2 Note that the LEDs of all channels are out.
To simulate starting the first motor press and release push-button 1: the output relay makes a click-clack sound indicating the momentary making and then breaking of the NO contact. An ohmmeter across terminals 1 A and lB will confirm this. Because no feedback signal is reaching terminals S1 and SC1 (See section 2.8), the NC output relay 2 momentarily clicks open as it is programmed for Auto-Off. An ohmmeter across 2A and 2B will show this. As you simulated the manual switching On and the automatic switching Off (Auto-Off) of the motor, the LED of Chan. #1 will have blinked, then gone out. If a voltage of 12 or 24 V had been applied to S1+ and SC1 within two seconds of the momentary starting pulse, LED 1 would have stayed lit until reception of a disconnect command. A command to disconnect can reach the IND-8 in three ways:

  1. By interrupting the feedback (monitoring) signal
  2. By telephone, by pressing 1, then 0 (see 6.1 to 6.5)
  3. On site, by pressing push-button 2

NOTE: Because this configuration uses contacts programmed for momentary action, the LED of channel 2 will not light up.

9.3.3 On-site stopping of Motor #1
Pressing and releasing push-button 2 momentarily opens the NC contact of channel 2. Verify this with an ohmmeter across 2A and 2B. Still using the example of Fig.3, the second Control Circuit, the one using push-buttons 3 and 4, will respond the same way as the Control Circuit for motor #1. The operation of channels 5 to 8 is covered in section 9.3.4.

9.3.4 Control Circuits 3 and 4, controlling heating elements
Please refer to lines 14 to l7, Fig.3; a clock-switch causes the temperature of a liquid in a tank to be raised to 85o C and to be maintained there every day between 4:30 AM and 4:30 PM. Two Control Circuits connected to the IND-8 serve to override or interrupt the action of the clock-switch. The time-delay contact (line 17) keeps the monitoring (feedback) circuit temporarily activated during the time it takes the heaters to raise the temperature of the liquid and thus close the contact of thermostat THSW2. When the user telephones the IND-8, this contact of THSW2 allows confirmation that the elements are operating normally.

9.3.5 Test-switching the Control Circuit of Output Channel 5
Press and release push button 5: the NO contact will close (continuous action). Because there is no feedback signal to monitoring terminals S5+ and SC2, the Auto-Off function of the IND-8 will reopen the contact (check these actions with an ohmmeter across 5A and 5B). LED #5 will have blinked, then gone out. If a voltage of 12 or 24 V had been applied to monitoring terminals S5+ and SC2 during first two seconds after the On-command, Output Channel 5 would have stayed closed and LED #5 lit until the communication of a disconnect command; this can be given in three ways:

  1. by interrupting the feedback signal;
  2. by telephone, pressing 5, then 0 (see sections 6.1 through 6.5);
  3. by pressing and releasing push-button 5.

NOTE: When an Output Channel is programmed for continuous contact action, on-site On and Off switching commands are both made by means of the same push-button.

9.3.6 Switching and receiving confirmation by telephone
The tests described in 9.3.2 to 9.3.4 were done using the push-buttons of the IND-8. We suggest you now repeat these tests with a telephone, following the instructions in sections 6.1 to 6.5.

NOTE: you will notice that after each command to switch a load On the device will respond with a descending tone instead of an ascending one, because of the lack of feedback signals. When the IND-8 repeats a low tone 5 times, this indicates that the monitoring signal (feedback) does not correspond to the last command received (See sections 2.7 and 2.8).

9.3.7 User's recap of commands and channel numbers
We suggest that the user should keep within easy reach a table recapping the function of each channel, the description of the load controlled by it, and the inputs required to access the IND-8. Continuing our example, such a table will show the following information:

Start motor 1 1 Telephone the IND-8
after 4 rings ... Beep
enter access code 1989 ... Beep
enter load #, followed by :
1 = connect; 2 = disconnect; or 9 = confirm ... Beep
Stop motor 1 2 S
Start motor 2 3
Stop motor 2 4 S
Override clock-switch contact 5
Interrupt clock-switch contact 6  
Connect or disconnect :    
external circuit 1 7 enter another command or tell the IND-8 to
"hang-up" by pressing * ...long Beep = end.
Connect or disconnect:  
external circuit 2 8