Recent content by patrickduis

of course.

The modbus slave I talked about has a register where you should write the state of the relays in. It is a low power contact, so drive another bigger relay using this contact.

See our Promux modbus RTU RS-485 or TCP ethernet modules. Work extremely reliably, simple and very rugged. Hardware has automotive electronics specifications. See: https://cascade.net/en/modular-plcs/ See all modules in the brochures. RTU: see the PM4RO with relay outputs on page 49 TCP: see...

I would contact ABB, they are specialized in transformers and transformer monitoring systems.

You said you use a VFD. Most VFDs have a ModBUS RTU RS-485 connection. With that you can read out all the current, voltage and power signals: problem solved.

There are several devices for that. They integrate the voltage and calculate the true RMS voltage (equivalent DC like voltage of the AC signal that gives the same effect). For example, a true RMS Fluke 179 multimeter can measure voltage, True RMS up to 1000Vac with a frequency range of...

depends on what the interface IC of the device does when switched off. normal people would design it in such a way, that the outputs connected to the modbus A and B lines goe in 3-state, but you never know.... Depends on the electronic design.

how is the modbus interface of the master and slave(s) configured? They must be the same. Sometimes, because of a bad interface, bits get damages in the communication, don't forget to terminate the RS-485 lines with 120ohm between the A and B line. And use proper shielded and impedance corrected...

I sometimes encountered a problem with slaves that don't support multi read function codes. Then I set the driver in Pro-face manually from write function call 10 (multiple) to 06 (single) in the 40000x area...... Maybe you can try that also......

Contact Guido of Ex-Machinery, he is an expert in this matter https://ex-machinery.com/nl/contact/

Can you specify the Ex class you talk about?

Sometimes you need to swap the A and B lines on RS485. I think you already tried that. I use a lot of pro-face touchpanels, and the 1st address I always read from a temperature controller is (decimal) 400001 using the generic modbus driver. The list on page 21 of the DRS-240 manual shows...

Dear David, Yes, we have been busy over the years. The RKC Instrument SB1 is specially developed for heat-tracing applications. Therefore it is fitted with an internal solid state relay. You can install it near the pipe to be heated. Connect the 230V heating element, 230V power supply you're...

Glad that I could be of some help to get it working. Pro-face uses 2 types of ports. Some only have the A, B and GND signals, those ports are for example for Canbus//Profibus. There you don't need to put the enable jumpers. I always check the hardware manual for specific Pro-face touchpanels...

I think we found the solution to your problem. The SG is the GND line of the RS-485 connection. You must use that for the communication. Please consult the hardware manual page 36 for the connector, your unit has only 1 connector so you need COM1 in GP Pro Ex. See...