I am currently exploring the feasibility of utilizing a 1756-IB16I (or a similar dc input module) to accommodate a 24vdc input pulse frequency of 80 pulses per second for a flow application. The system involves seven (7) pulse meters generating 1600 pulses per gallon at a flow rate of 3 gallons per minute (gpm). To handle this setup, I will require eight (4) 1756-HSC modules as the HSC module only supports two inputs. Thank you.
I possess an outdated specification sheet indicating that the input delay time should not exceed 1ms, along with filter times of 0ms, 1ms, or 2ms. It is essential to take into account your module's Requested Packet Interval (RPI) and the Programmable Logic Controller's (PLC) scan time. With 80 pulses per second, an edge occurs approximately every 6ms, allowing a swift timed interrupt to capture it if your RPI is set at a minimal value, such as 1ms. Alternatively, you may consider exploring the capabilities of the 1756-IB16IF, a high-speed input module. Although I do not have the datasheet readily available, it should be easily accessible on RA's website. To effectively utilize this module, you will still require a rapid timed interrupt and appropriate RPI settings, unless the module already incorporates high-speed counter functionality.
For those looking to reduce expenses, consider exploring the ADAM-6151EI-AE - a 16-channel Isolated DI Ethernet/IP Module. This model offers high-speed performance and cost savings.
Are you interested in the 1756-LSC8xIB8I counter module, which comes equipped with 8 channels?
That is a unique find that I haven't come across yet.
jstolaruk mentioned that they haven't seen this particular low-speed counter before. They used it over a decade ago and are surprised that it is not more well-known. This type of counter is far superior to a standard input for counting purposes.
Your calculations seem correct, given your current setup, but there may be a more efficient way to approach this. If you could use a pulse input module with a higher bandwidth, like a 1756-IF16, you could connect more meters onto a single module, mitigating the need for a large number of HSC modules. This could cut down on system complexity and potentially save costs. Just make sure it can handle your 80 pulses per second requirement!
Your calculations seem accurate when considering the limitations of the 1756-HSC modules. However, it's important to also factor in your system's latency and the potential for input pulse overshoot. You've also assumed an ideal condition of a steady 3 gpm flow rate; yet in real-world applications, flow rates can often fluctuate. To buffer against these potential issues, consider allocating spare capacity. Also, look into if your PLC processor can efficiently handle the overhead of the additional modules.
It sounds like an interesting project you have on your hands! Just keep in mind that the 1756-IB16I should adequately handle the input pulses at that frequency, but you might want to double-check the response times and any debounce filters to ensure you capture all pulses without missing any, especially since you’re dealing with multiple flow meters. Also, consider the total pulse count since your flow rate can ramp up; using the HSC modules strategically will definitely help manage that situation. Good luck!
It sounds like you're diving into a pretty interesting setup! The 1756-IB16I should handle your 24VDC input pulses just fine, especially since it's designed for robust applications like this. Just make sure to account for the total pulse load on your input module; with 1,600 pulses per gallon at 3 GPM, you will definitely have a pretty active input stream. Your decision to use four 1756-HSC modules makes sense given the pulse frequency—it's always better to have dedicated channels to ensure you’re capturing everything accurately. Are you planning to implement any filtering or debounce logic to manage any potential noise from the pulse meters?
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Answer: - Yes, the 1756-IB16I module (or a similar dc input module) can handle a 24vdc input pulse frequency of 80 pulses per second for a flow application.
Answer: - The system involves seven (7) pulse meters generating 1600 pulses per gallon.
Answer: - The flow rate of the system is 3 gallons per minute (gpm).
Answer: - It is required to use eight (4) 1756-HSC modules because each HSC module supports only two inputs, and in this setup, multiple inputs need to be handled.
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