Timing measurement using PLCs with 1 ms resolution


Thread Starter

Jim Cai

Hi all,

I am looking for a modbus type PLC to measurement timings between two digital status change. The resolution is about 1 ms. Is there any controllers that can do the timing and report the data directly to HMI through Modbus/RTU.

Thanks in advance !

Doug McQueen ESI Electric Supply Inc.

Idea! look at the the modicon tsx plc with a onboard counter VERY IMPORTANT!! Use A as on in-put and B as the other, then measure between the two moving the on status into a timer YEA this will be fun. Which ever plc you use and if
you choose to ponder the Wild idea of this high speed counter. A onboard counter with MODBUS
port built in will probably be to your advantage. good luck thats a cool one.

Al Pawlowski, PE

I think many of the RTU's made for Utility power SCADA can time-stamp/resolve DI changes to 1ms. I believe QEI (Quindar Electronics) is one of them.

Tony Chambers

Have a look at Ronan Engineering, we use a couple of their X500E Sequence Events Recorder's These are Rack mounted PC based equipment's with 1ms stamping, we use them for ESD Events recording but I believe they are used in the power industry

Cheers Tony Chambers.
[email protected]
Norfolk, UK
A product that may fit your requirements is made by Control Technology of Aurora, Colorado. They make a standalone event monitor with a 1000 event
buffer, 1 ms resolution, IRIG-B signal input for time from a standalone or GPS time source, and.... Modbus RTU protocol.

They make a PLC module for the PLC-5, but it seems that what you need isn't really a PLC, more of a time-logger RTU. They work like a charm.


Ken Roach
A-B Seattle
An additional note:

Control Technology is now located in Centennial, Colorado. The stand-alone module we manufacture is the 3000-TS series. For more information:

web: http://www.ctii-usa.com
phone: 303-400-0547