> List, > I'm interested in hearing how different locations/users are > using IA function blocks to start, stop and alarm motors. We have > existing installations that were put in service using motor blocks, > (MTR), in conjunction with ladder logic, even before GDEV blocks were > available. Many of the motors use a single DCS Contact Output as a > Start/Stop and a Contact Input as a motor status/run confirm. Many of > our motors have a Remote/Local switch located near the field motor. > Remote enables DCS Start/Stop, and Local enables the motor to=20 > Start/Stop > from the field, while disabling the DCS from starting the motor. This sounds like what we have. > We > mostly used the 3 wire option which pulses the COUT_1, (START), and > COUT_2, (STOP), parameters. The Remote DCS Start Contact is not > sealed/latched at the motor starter with an auxiliary starter=20 > contact so > the DCS needs to hold the pulsed COUT_1 true to keep the=20 > motor running. > To accomplish that we created a seal-in rung in the ladder logic that > contained the DCS run contact input and the DCS Start/Stop Contact > output. We use the MTR Block in the 2 wire configuration. The block turns on the output, and will hold the output if it sees the feedback from the auxillery. It is sealed/latch in the MTR block. > output. In short, I want the pulsed output to latch in if the motor > contactor engages and feeds back to the DCS that the motor is running, > but I want the pulse to go away and generate a mismatch alarm and kill > the Run request if the motor fails to start. Most of the motors are set this way for us. Set the reset mismatch = option, RSMMOP 1, and when the block has timed out, the start output will go = off. Mark _______________________________________________________________________ This mailing list is neither sponsored nor endorsed by Invensys Process Systems (formerly The Foxboro Company). Use the info you obtain here at your own risks. Read http://www.thecassandraproject.org/disclaimer.html foxboro mailing list: http://www.freelists.org/list/foxboro to subscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=join to unsubscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave