You make a good point. One-shot mode and Off Delay will work roughly the same with one minor difference. In One-Shot mode the timer starts when the trigger signal 'S' is applied to the relay. If the relay is not retriggered before the end of 'T', then the output will shut off.
In Off Delay mode, the timer starts when the trigger signal 'S' goes away. I guess you could look at it as rising edge vs falling edge. Here is a link timing diagrams for this relay. http://magnecraft.thomasnet.com/Asset/Stránky-z-Section-5_3-2.pdf
Probably does not matter which one you use. I'm probably just partial to One-Shot because it's a function I've implemented a lot in the past with 555 timers.
I agree, I did not consider the odds of a high latch during the reset input pulse. Retrig one shot is the fail safe route to go.
You initial post gets 5 stars simply because ( Quoting the AnalogKid's signature 😞
‘It’s the questions that drive us.”
You can thank Trinity's line from "The Matrix" for my signature, seemed fitting for this Forum
It looks like I'm waking a dead thread, perhaps with some risk, but I'm seeing the exact same behavior on my fairly new cFP-1804. That is to say that, when I disconnect the Ethernet cable for more than 5 seconds or so, the link lights turns off and the device becomes unresponsive. We're using this cFP model in a few of our products, and the possibility of communication failure at a remote site makes me rather nervous.
There was a lengthy discussion on watchdog timers, but I'm wondering if the problem on the cFP device itself was ever resolved? Is there any known workaround within the scope of the cFP-1804? Has any new firmware been released?
I've tried the following:
1. Unchecking the "Halt system if TCP/IP fails" checkbox in MAX
2. Verifying that the "WatchdogTimeout" variable is set to zero in the Distributed System Manager
Has anyone figured out a way around the Ethernet issue?
Thanks in advance,
Hi Mr. Jim,
Did you check to ensure that the Network Watchdog Configuration in MAX was set to Disabled? See the picture below for its location. Also, these may or may not be helpful:
NI Developer Zone: Guarding Against Network Failures: How to Configure the Network Watchdog Timer fo... (this is an older document using FieldPoint Explorer, but relavent).