I am having some issues with a water meter connected to a WC8 (firmware v03.03.31).
The water meter uses a simple contact closure pulse relay. I have connected it to TTL Input 1 on the WC8 and enabled TTL1 as counter.
This seems to be working except for what I think is some switch bouncing, frequently causing the count to jump by 3 or 4 counts per pulse. This is more pronounced with low water flows when I think the relays closes less quickly. At full flow the meter pulses about once a second or slightly less, and still bounces a little bit.
I have looked at various options such as a RC circuit (+/- a logic chip like the 74HC14) but this would require pulling apart the housing which is mounted in a wall box inside a pool pump house. Quite a bit of time involved. And I am uncertain what would be appropriate values for the two resistors and the cap anyway.
Other things I have read suggest using a 'software' debouncing option. But I am not very familiar with PLC. And reading through these forums I can't see that anyone has done this with the TTL1 COUNTER option in the WC8 PLC software.
Any advice would be appreciated.
Marty
The water meter uses a simple contact closure pulse relay. I have connected it to TTL Input 1 on the WC8 and enabled TTL1 as counter.
This seems to be working except for what I think is some switch bouncing, frequently causing the count to jump by 3 or 4 counts per pulse. This is more pronounced with low water flows when I think the relays closes less quickly. At full flow the meter pulses about once a second or slightly less, and still bounces a little bit.
I have looked at various options such as a RC circuit (+/- a logic chip like the 74HC14) but this would require pulling apart the housing which is mounted in a wall box inside a pool pump house. Quite a bit of time involved. And I am uncertain what would be appropriate values for the two resistors and the cap anyway.
Other things I have read suggest using a 'software' debouncing option. But I am not very familiar with PLC. And reading through these forums I can't see that anyone has done this with the TTL1 COUNTER option in the WC8 PLC software.
Any advice would be appreciated.
Marty