Programmable Logic Controllers
Pico Controllers
1760-L18, 1760-L20 Time Functions
Timing Relay T Functional Description
The devices provide 16 timing relays T01...T16.
A timing relay can be used to simulate a timer function in which you can change the switching times for the on and off switching of a switching contact. The configurable delay times can be between 10 ms and 99 h 59 min. Positive values, such as analog input values or the actual values of counter and timing relays, can be used as a setpoint. Minimum time setting: 0.01 s (10 ms).
A timing relay can be used in your circuit diagram both as a coil or as a contact (switch contact).
You can activate a timing relay in your circuit diagram as a coil and use its time-controlled switch contact in a contact field.
For starting, stopping or resetting a timing relay, add it to your circuit diagram as a coil (in the coil field). In the Coil function area you define which of these three functions are to be triggered by the associated contacts.
In order for the timing relay to operate as a switch, add it in the circuit diagram as a contact (in the contact field). Choose the Properties field window, Circuit Diagram Element tab, Contact area to define the switch function of the contact as a make or break contact.
The timer function, i.e. the way in which a timing relay controls the switching time, depends primarily on the mode configured.
Linking and Par`ameter Assignment of a Timing Relay
Requirements: You have included a control relay in the project and have switched to Circuit Diagram View.
Activating a timing relay
- Position a T timing relay operand in the circuit diagram on a coil field so that you can control a switch time.
- In the Circuit Diagram Element tab of the Properties field window select the required function block number between 1 and 16 and the Trigger coil function. The operand TTxx will now be shown in the circuit diagram.
- Select the required mode and the time range.
- In the Parameters tab set the setpoint for the input I1 and, if necessary, I2 if you have selected a suitable operating mode. At the end of this section is a description of the selectable operands - Constant or actual value of another function relay.
- If required, change the enable of the parameter display and/or write a comment for the selected operand.
- Connect the TTxx coil with an appropriate contact for triggering. The timing relay is incremented as long as the coil is set to 1. If you are using single pulse mode, the timing relay will start when a rising edge is detected at TTxx.
Evaluation of a timing relay
To use the time-controlled switch contact of the relay, the T timing relay, which is linked as a coil, must be added to the circuit diagram again on a contact field. The contact switches according to the operating mode set and the setpoint.
- Position the T timing relay on a contact field and select the same function block number in the Circuit Diagram Element tab that you have assigned to its corresponding coil.
- If required, change the switch function of the contact from break to make contact.
- Connect this Txx contact in the circuit diagram.
Resetting a timing relay
- In order to reset the timing relay and the associated switching contact, position the T timing relay that has already been linked as a trigger coil once more on a coil field in your circuit diagram.
- In the Circuit Diagram Element tab select the function block number between 1 and 16 that has already been used for the activation and the Reset coil function. The operand RTxx will now be shown in the circuit diagram.
- Connect the RTxx coil with an appropriate contact for triggering.
Circuit diagram elements and parameters
| Description | Note | |
|---|---|---|
| Function relay inputs (setpoints) | ||
| I1 | Time setpoint 1 | See the following note |
| I2 | Time setpoint 2 (for operating mode with 2 setpoints, e.g. flashing) | |
| Function relay output | ||
| T | Integer value depending on the configured time range. 0 to max. 99990 in the Second:millisecond time range This output can be used as a setpoint for the C counter relay, other T timing relays and the A analog value comparator as well as an actual value for the D text display. |
|
| Contact | ||
| Txx | Switching contact | |
| Coil function | Designation | |
| Trigger | The timing relay is started when a rising edge (Trigger) is detected. This coil must then be set to 1 (Enable) continuously until the required time has elapsed. Only in Single pulse mode is one rising edge enough to trigger the required timing response. |
TTxx |
| Reset | Reset coil function: 1 resets the timing relay and the associated switch contact. | RTxx |
| Stop | Stop coil The timing relay is stopped. The started time will cease to time out whilst the HTxx Stop coil is set to 1. The stopped time will continue to time out if the signal at the Stop coil HTxx is reset to 0. If the stop coil HTxx is set to 1 with a rising edge at the trigger coil TTxx, the transfer of the time setpoint will be delayed for as long as the signal at HTxx is 1. The status change on the switch contact is delayed in the same way. |
HTxx |
| Mode | ||
| On-delayed | On-delayed switching | |
| On-delayed + T(rnd) | On-delayed switching with random time range | |
| Off-delayed | Off-delayed switching | |
| Off-delayed + T(rnd) | Off-delayed switching with random time range | |
| On/off delayed | On and off delayed switching there are two time setpoints to be configured | |
| On/Off-delayed + T(rnd) | On and off delayed switching with random time range there are two time setpoints to be configured | |
| Single pulse | Single pulse switching | Normalizes input signals of different pulse lengths to a fixed pulse length at the switch contact of the timing relay. |
| Flashing | Flash switching — there are two time setpoints to be configured.
|
Time values: S1=Mark time S2=Space time |
| Time range | ||
| S | Second:Milliseconds Configurable as a constant: 00.00 to 99.99 (s.ms), max. 99990 ms. |
Resolution: 10 ms |
| M : S | Minutes:Seconds Configurable: 00:01 to 99:59 (min:s), max. 5999 sec. |
Resolution: 1 sec |
| H : M | Hours:Minutes Configurable: 00:01 to 99:59 (h:min), max. 5999 min. | Resolution: 1 min |
| Parameter display | ||
| Call enabled | The parameters can be viewed on the device. | |
Note on the minimum time setting: If a time value is less than the program cycle time, the elapsed time will not be recognized until the next cycle. This may cause unpredictable switching states.
Operand Selection for the Inputs I1 and I2 (time setpoints)
| Operand | Description |
|---|---|
| Constant | 0...99:59 (time range »M : S/H: M) or 0 - 99.99 (time range S) |
| C | Output of a counter relay (e.g. C3QV) If the counter actual value is greater than the maximum permissible setpoint of the configured time range, the setpoint will be limited to this maximum value. Example: You have configured the time range M : S and the counter actual value is 31333. The device limits the setpoint to 5999 min. |
| IA | Analog input of the device (I7 = IA1, I8 = IA2, I11 = IA3, I12 = IA4), if available. Note the relationship described below between the permissible analog value and the timing relay setpoint. |
| T | Output of a timing relay (e.g. T4QV). |
Analog value and timing relay setpoint
If you wish to use variable values as a timing relay setpoint, such as an analog input, the following conversion rules apply, depending on the time base configured.
S time base
Equation: Time setpoint = ( Variable value*10) in [ms]
| Variable value | Time setpoint in [s] |
|---|---|
| 0 (Minimum) | 00.000 |
| 100 | 01.000 |
| 300 | 03.000 |
| 500 | 05.000 |
| 1023 (Maximum) | 10.230 |
M:S time base
Rule: Time setpoint = Variable value/60
Integer = Number of minutes
Remainder = Number of seconds
| Variable value | Time setpoint in [M:S] |
|---|---|
| 0 (Minimum) | 00.000 |
| 100 | 01:040 |
| 300 | 05.000 |
| 500 | 08:020 |
| 1023 (Maximum) | 17:003 |
Time base H:M
Rule: Time setpoint = Variable value/60
Integer = Number of hours
Remainder = Number of minutes
| Variable value | Time setpoint in [H:M] |
|---|---|
| 0 (Minimum) | 00.000 |
| 100 | 01:040 |
| 300 | 05.000 |
| 606 | 10:006 |
| 1023 (Maximum) | 17:003 |
Note: You can only use analog values as setpoints if the value of the analog input is stable. Fluctuating analog values impair a reproducible timing response.
Retention
Selected timing relays can be run with retentive actual values. If a timing relay is retentive, the actual value is retained when the operating mode is changed from RUN to STOP and when the power supply is switched off. When the control relay is restarted in RUN mode, the timing relay continues with the retentively stored actual value.
In Project View, select in the System tab which of the timing relays T7, T8 and T13 to T16 are to be kept retentive. The retentive actual value requires 4 bytes of memory.